How to make bootstrap alert popup in another page when clicking on a button

Im trying to make an admin page where if i click on the button ‘send’, the message will be sent and there will popup a bootstrap alert on the employee page.
I have already the bootstrap alert setup, the message for the first time is shown. After I close and i send a message again i dont see any alert. I think it needs to be triggered when i click on the send button but im struggling about how to do that. Hope anyone can show me a simple way.
Here is the code for the admin page to send:

Angular ngOnInit javascript errrors when i load page, but the page works as intended

I have a page in angular and in ngOnInit function i load my data. The data loads correctly and it is shown on page, everything seems to work, the only problem is in console i get a lot of javascript errors cannot read property ‘propertyName’. Any help of how i can get rid of those errors would be appresiated.