‘Cannot Access a closed file’ error on some files

I’m getting Cannot Access a closed file on some files when I try to upload them. I’m creating a small web app, when a user creates an account on the website, they are required to upload a file. Once they have uploaded the file, I should see it in MongoDB. The issue is some files are uploaded successfully while others create errors. This is the exact error msg from the log:

Postback Request of ASP.NET Controls are taking too much time

I have created an asp.net website http://www.oureasymart.com which is working fine In localhost. but after hosting it to godaddy when an asp.net control like button is clicked then it is taking too much time around 1 minute to perform its operation. This problem is for every asp.net control of each page.
I think there is no issue with code behind or click event because I tried a simple Response.Redirect() method to move to next page on click of that button but still it is taking same time. Also I tried to call same method with the help of Jquery Ajax and it is working fine. I also enabled tracing in which I checked there is no event which is taking even 1 second. Please have a look at the code and screenshot of trace info and suggest what may be the issue.
TRACE INFO : https://drive.google.com/file/d/19Cl6wpe_Y20FCzxI9d0bUvj8BdaUdgjR/view?usp=drivesdk