Would be good that SQL Search authenticated through Azure Active Directory - Universal with MFA.

SQL Search version: 3.4.2.2567
Error log:
[78] ERROR RedGate.SQLSearch.Addin.Tab.DatabaseConnector - Could not load database list
System.Data.SqlClient.SqlException (0x80131904): Cannot open server "XXXXX" requested by the login. The login failed.
...at RedGate.SQLSearch.Addin.Tab.DatabaseConnector.OnlineDatabasesForInstance(String connectionString)
Error Number:40532,State:1,Class:20
[1] ERROR RedGate.SQLSearch.Addin.LoggingErrorHandler - Failed to get the object hierarchy
Exception: Exception has been thrown by the target of an invocation.
...at RedGate.SQLSearch.Addin.ObjectExplorer.SSMS.SsmsObjectExplorer.RootNode(String connectionString, IErrorHandler errorHandler)