IIS Application Pool (3CX Caller ID AppPool) Stops
All attempts to access the application result in a 503 Service Not Available error and the application pool stops. Switching the application pool allows the site to load, but unable to log in.
My first guess is that the username and password is incorrect for the application pool. In IIS, select the application pool, then select "Advanced" in the far right-hand panel, then edit the "Identity" field. By default, this should be set to ./VoIPToys with the appropriate password. You can change it to another account, but that account will need database access rights. That's why changing to another pool allows you to see the web pages, but you get errors when trying to access the database.
Another option would be to change your database connection string to use SQL Authentication (I suspect you are using Windows authentication). You can also contact us on live chat. We are here to help!