Entity Framework Core 7 connection certificate trust exception

it is not a bug in EF Core 7.0, instead it is improved security. Microsoft suggest following 3 solution, which ever applies to you.

1. install a valid certificate.
2. Add TrustServerCertificate=True to the connectionstring
3. Add Encrypt=False to the connectionstring

Old behavior
SqlClient connection strings use Encrypt=False by default. This allows connections on development machines where the local server does not have a valid certificate.

New behavior
SqlClient connection strings use Encrypt=True by default. This means that:

The server must be configured with a valid certificate
The client must trust this certificate
If these conditions are not met, then a SqlException will be thrown. For example:

A connection was successfully established with the server, but then an error occurred during the login process. (provider: SSL Provider, error: 0 – The certificate chain was issued by an authority that is not trusted.)

https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-7.0/breaking-changes