Why do I get an error when comparing data in Visual Studio?

Question

Database

When comparing the data of two databases that are identical in structure, but with completely different values, the following error occurs:

Password and login and all connection settings are correct. Since the database works in a program installed on several machines, and the database itself is located on the database server.
It was checked on a test machine with the installation of a new server and restoration from a backup. Same error.