Additional SQL Server features and topics not covered by specific categories
Well, guys, I found the problem, it was a wrong and 'hidden' Connection String.
I created a new database with a different name, but the error in the browser after launching the app in my localhost kept pointing to the old database name.
After that, I searched for the old database name throughout the project and discovered that my colleague had added a partial class inside the DataAccess project of the ASP.NET application, which runs in development mode and contains his connection string.
I changed that, and now everything is working fine. All I knew was that the connection string should be in Program.cs or appsettings.json, and no other places.
Thank you all for your time..¡