Login failed for user ‘IIS APPPOOLASP.NET v4.0’

I have a web project (C# Asp.Net, EF 4, MS SQL 2008 and IIS 7) and I need to migrate it to IIS 7 locally (at the moment works fine with CASSINI).

Locally in IIS I have my Default Web Site with my deploy. Both my deploy and Default Web Site are on pool ASP.NET v4.0 (look image for settings) the pool target Framework 4 as my web project.
Login failed for user 'IIS APPPOOLASP.NET v4.0'
When visiting the site, the browser does not show the page and allow the browser to download the page instead.

I have other projects running on IIS locally and they work with no problems (but they do not use Entity Framework).

Using the Event Logger I see errors as below:

Exception information: 
    Exception type: EntityException 
    Exception message: The underlying provider failed on Open.
   at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)

    Login failed for user 'IIS APPPOOLASP.NET v4.0'.
       at System.Data.ProviderBase.DbConnectionPool.GetConnection(DbConnection owningObject)
       at System.Data.ProviderBase.DbConnectionFactory.GetConnection(DbConnection owningConnection)
       at System.Data.ProviderBase.DbConnectionClosed.OpenConnection(DbConnection outerConnection, DbConnectionFactory connectionFactory)
       at System.Data.SqlClient.SqlConnection.Open()
       at System.Data.EntityClient.EntityConnection.OpenStoreConnectionIf(Boolean openCondition, DbConnection storeConnectionToOpen, DbConnection originalConnection, String exceptionCode, String attemptedOperation, Boolean& closeStoreConnectionOnFailure)

Related question

You can read in the resources on this question that permissions must be granted on MS SQL 2008 manually as arift explain in his answer.
Using IIS 7.5 and MS SQL 2008 R2, setting manually permission should not be necessary.


Thank you for visiting the Q&A section on Magenaut. Please note that all the answers may not help you solve the issue immediately. So please treat them as advisements. If you found the post helpful (or not), leave a comment & I’ll get back to you as soon as possible.

Method 1

Looks like it’s failing trying to open a connection to SQL Server.

You need to add a login to SQL Server for IIS APPPOOLASP.NET v4.0 and grant permissions to the database.

In SSMS, under the server, expand Security, then right click Logins and select “New Login…”.

In the New Login dialog, enter the app pool as the login name and click “OK”.

enter image description here

You can then right click the login for the app pool, select Properties and select “User Mapping”. Check the appropriate database, and the appropriate roles. I think you could just select db_datareader and db_datawriter, but I think you would still need to grant permissions to execute stored procedures if you do that through EF. You can check the details for the roles here.

Method 2

You can change the ApplicationPoolIdentity from IIS7 -> Application Pools -> Advanced Settings.

Under ApplicationPoolIdentity you will find local system. This will make your application run under NT AUTHORITYSYSTEM, which is an existing login for the database by default.

Edit: Before applying this suggestion you should note and understand the security implications.

Method 3

I solved this problem using sql as following image.

Right click on db-> properties -> permission -> View Server permission -> and then select IIS APPPOOLASP.NET v4.0 and grant permission.


Method 4

ensure you have…


in your connection String

Method 5

Run this sql script

IF NOT EXISTS (SELECT name FROM sys.server_principals WHERE name = 'IIS APPPOOLDefaultAppPool')
CREATE USER [WebDatabaseUser] 
EXEC sp_addrolemember 'db_owner', 'WebDatabaseUser'

Method 6

If in the connection string you have specified:

User ID=xxx;Password=yyy

but in the connection string there is:


SQL Server will use Windows Authentication, so your connection values will be ignored and overridden (IIS will use the Windows account specified in Identity user profile).
more info here

The same applies if in the connection string there is:

 Integrated Security = true;


 Integrated Security = SSPI;

because Windows Authentication will be used to connect to the database server.
more info here

Method 7

go to iis -> application pools -> find your application pool used in application

enter image description here

select your application pool used for the application right click select advanced settings

enter image description here

Select application pool identity
enter image description here

select built in as Local System
and click ok

Method 8

1_in SqlServer Security=>Login=>NT AUTHORITYSYSTEM=>RightClick=>Property=>UserMaping=>Select YourDatabse=>Public&&Owner Select=>OK
2_In IIs Application Pools DefaultAppPool=>Advance Setting=>Identity=>LocalSystem=>Ok

Method 9

I hate the ApplicationPoolIdentity. I always set a Windows User Account as the account on AppPools.

As adrift says, it does sound like a database security issue. So create an NT user account, assign it to the ASP.NET v4.0 AppPool and then grant it permission on the website folder and to the relevant table(s) in SQL.

Method 10

First thing you need to clear if you are using windows authentication and you are not mentioning any username password in your connection string then:

What happens when you run your code through localhost: when you run your wcf test client from localhost, it will be able to communicate to database as local debug mode application is calling database by your account’s service. So it has access to database because devenv.exe is running under your user account.

But when you deploy your web service in IIS. Now understand this service runs under IIS not under your account. So you need to assign access rights to IIS service to access the sql server for windows authentication. Here your web service would not be able to communicate to the SQL server because of access rights issue and Login Failed for user_______ (here your user will come)

So if you are using windows authentication to connect your database, you just have to change the IIS Application pool settings. You need to change IIS Application pool’s identity to local System.

Below are the Steps for windows authentication WCF:

1) Open IIS (windows+R (run) then type inetmgr, then click ok)

2) double click your PC name under Connections

3) Click Application Pools

4) Select your app pool (DefaultAppPool)

5) Then under actions on the right click Advanced Settings:

6) Go to Process Model section and

7) click on Identity.

8) Now select LocalSystem.

Now open your sql server management studio:
open run-> then type ssms ->then press ok
In ssms, login using your windows authentication account.
Open security tab expand logins tab then you will be able to view your account.

Now open properties of your account
go to userMapping then select the database you want to connect
then check the role membership services you want to use for the selected database. click ok.

(For network services i.e. intranet users you need to configure above settings for NT AUTHORITYSYSTEM user too)

add Trusted_Connection=True; property in your connection string. Save it & deploy the web service. Restart app pool.

you will be able to connect the database now.

Method 11

Don’t use Integrated Security.
Use User Id=yourUser; pwd=yourPwd;

This solves the problem.

Method 12

I had to create a user `IIS APPPOOLDefaultAppPool’ as shown below in SQL Server. Security > Login > Right click and press ‘New Login’. You only enter the username as show in red in the screen.

Login failed for user 'IIS APPPOOLASP.NET v4.0'

Then go into that new user properties, check the database this user will access (marked in blue below) and select db_owner as well. I had to select because although connection was working but subsequent SELECT queries didn’t had the access if this was not selected.

Login failed for user 'IIS APPPOOLASP.NET v4.0'

These two should do it. Basically you are making the new user owner for the database so it has full access.

You don’t need to restart SQL Server or anything, should work.

Method 13

I had this issue and it was actually caused by something different – I had the ‘IIS APPPOOLASP.NET v4.0’ user in my database but it still wasn’t working.

I had recently upgraded my SQL Server Install and in the process the User had become disconnected from the Login – so there was an ‘IIS APPPOOLASP.NET v4.0’ under Database -> Security -> Users BUT no User not under Security -> Logins.

Added the Login ‘IIS APPPOOLASP.NET v4.0’ to Security -> Logins, SQL Server automatically mapped it to the User in the database (this used to have to be done manually) and problem fixed.

Method 14

I had this message and I use Windows Authentication on the web server.

I wanted the currently authenticated web user to be authenticated against the database, rather than using the IIS APPPOOLASP.NET v4 User specified in the App Pool.

I found by entering the following in the web.config fixed this for me:

  <identity impersonate="true" />


I see other Answers regarding creating the AppPool username in the SQL DB or just to use SQL Auth. Both would be correct if you didn’t want to capture or secure individual Windows users inside SQL.


Method 15

I Have the same problem I solved it by changing Integrated Security=True to false
now its working

Method 16

Setting the identity only makes this work in my pages.

Method 17

Cassini runs your website as your own user identity when you start up the Visual Studio application. IIS runs your website as an App Pool Identity. Unless the App Pool Identity is granted access to the Database, you get errors.

IIS introduced App Pool Identity to improve security. You can run websites under the default App Pool Identity, or Create a new App Pool with its own name, or Create a new App Pool with its own name that runs under a User Account (usually Domain Account).

In networked situations (that are not in Azure) you can make a new App Pool run under an Active Directory Domain user account; I prefer this over the machine account. Doing so gives granular security and granular access to network resources, including databases. Each website runs on a different App Pool (and each of those runs under its own Domain User account).

Continue to use Windows Integrated Security in all Connection Strings. In SQL Server, add the Domain users as logins and grant permissions to databases, tables, SP etc. on a per website basis. E.g. DB1 used by Website1 has a login for User1 because Website1 runs on an App Pool as User1.

One challenge with deploying from the Visual Studio built-in DB (e.g. LocalDB) and built-in Web Server to a production environment derives from the fact that the developer’s user SID and its ACLs are not to be used in a secure production environment. Microsoft provides tools for deployment. But pity the poor developer who is accustomed to everything just working out of the box in the new easy VS IDE with localDB and localWebServer, because these tools will be hard to use for that developer, especially for such a developer lacking SysAdmin and DBAdmin support or their specialized knowledge. Nonetheless deploying to Azure is easier than the enterprise network situation mentioned above.

Method 18

If you have your connection string added in your web.config, make sure that “Integrated Security=false;” so it would use the id and password specified in the web.config.

    <add providerName="System.Data.SqlClient" name="MyDbContext" connectionString="Data Source=localhost,1433;Initial Catalog=MyDatabase;user id=MyUserName;Password=MyPassword;Trusted_Connection=true;Integrated Security=false;" />

Method 19

As pointed out, Do not use Windows Authentication, Use SQL Server Authentication

Also if you created connection using “Server Connection” dialog, make sure to check the connections in web.config. It is likely that you created/modified connection and it was stored as trusted connection in web.config. Simply use this authentication

<add name="MyDBConnectionString" connectionString="Data Source=localhost;Initial Catalog=Finantial;User ID=xxx;Password=xxx" providerName="System.Data.SqlClient"/>

which should fix the error.

Method 20

Another way of granting permission to the database for the user IIS APPPOOLASP.NET v4.0 is as follows.
enter image description here

  1. Add New User with User Name and Login name as IIS APPPOOLASP.NET
    with your default schema.
  2. Go to Owner schema and Membership, Check db_datareader, db_datawriter

Method 21

You can face this wrong in specific database which is created after SSMS update. Open SSMS and select your databases and open your required database then click Security–> Users–> and right click on Users and click again on ‘New User’ and add ‘NT AUTHORITYAuthenticated Users’ and save you work and go to your Form on Web/Desktop whatever do you. Enjoy….

Method 22

Thought I’d post this as an answer as it is relevant to the question and can answer it in some cases.

That same message appears also if the database does not exist!

Be sure your connection string has no misspellings, is pointing to the right server instance, etc.

Method 23

In Asp.net webform,

this error fixed when installing asp.net from:

Server Manager > Manage > Add Role and Feature > Server Roles > Web Server (IIS) > Web Server > Application Development > ASP.NET 3.5/4.6 is installed.

my problem fixed.

Method 24

something similar happened to me what worked for me was changing the property Integrated Security = True to Integrated Security = false in the web.config of the website

Method 25

go to iis -> application pools -> find your application pool used in application -> click it and then click ‘Advance Settings’ in Actions panel. Find ‘Identity’ property and change it to localsystem.

Method 26

Have you done what @Teddy recommended and you STILL get the same error?

Make sure you’re changing the settings for the app pool that corresponds to your virtual directory and not the parent server. Each virtual directory has its own AppPool and doesn’t inherit.

Method 27

In DefaultAppPool set NetworkService in the Identity property and in Sql Server add User Network Service and give it the appropiate permissions to your database, that’s work very well for me, I’ve tested locally but I think this is the best configuration for connecting from any other computer in the network. when you set LocalSystem in the Identity in IIS that’s work well and it is not necessary to create any other user in Sql Server but I think that will not work in a network environment.

Method 28

I ran into the same problem testing ASP.NET Web API

Developed Web.Host in Visual Studio 2013 Express
Database created in SQL Server 2012 Express
Executed test using built in IIS Express (working)
Modified to use IIS Local (from properties page – web option)
Ran test with Fiddler
Received error – unable to open database for provider….
citing ‘APPPOOLDefaultAppPool’

Solution that worked.


Click on application pool ‘DefaultAppPool’
Set Identify = ‘ApplicationPoolIdentity’
Set .NET framework = v4.0 (even though my app was 4.5)

In SQL Server Management Studio

Right click on Security folder (under the SQL Server engine so applies to all tables)
Right click on User and add ‘IIS APPPOOLDefaultAppPool’
In securables on the ‘Grant’ column check the options you want to give.
Regarding the above if you are a DBA you probably know and want to control
what those options are. If you are like me a developer just wanted to test
your WEB API service which happens to also access SQL Server through EF 6
in MVC style then just check off everything. 🙂 Yes I know but it worked.

Method 29

In case you add a new login, make sure that under server properties ( rightclick -> properties)/security, authentication mode is set to both sqlserver and windows not only windows.

Method 30

Add “Everyone” under security. If you added the Server and the users logging in to the database, then this is something you are missing.
Hope this helps.

All methods was sourced from stackoverflow.com or stackexchange.com, is licensed under cc by-sa 2.5, cc by-sa 3.0 and cc by-sa 4.0

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