Problem Statement/Rationale

Compass adds authMechanism=DEFAULT to the connection string when username/password auth is selected under advanced connection options. According to the Auth Spec, authMechanism should be omitted if default authMechanism rules are desired. A user submitted a PR for the .NET/C# Driver because it is throwing an exception with the connection string copied from Compass.

Steps to Reproduce

1. Open a new Compass window.
2. Expand Advanced Connection Options.
3. Select the Authentication tab.
4. Choose Username/Password.

Expected Results

No authMechanism URI option should be present in the connection string.

Actual Results

authMechanism=DEFAULT is added to the connection string.

Additional Notes

PR submitted for the .NET/C# Driver: https://github.com/mongodb/mongo-csharp-driver/pull/1191