ORA-12631 using Database Links with Oracle DBMS 19c on Windows Server 2019

We had a set of long-time Oracle 12c Database installations (multiple instances on separate VMs) on Windows Server. Over the past year we transitioned to Oracle 19c on Windows Server 2019. We found that database links that worked in the 12c environment did not work in the 19c environment; a query referencing such a link would fail with the error ORA-12631: Username retrieval failed. SQLNET traces showed

naun5validate: SPP is NEGOTIATE 

naun5validate: SSPI: 0x8009030c error in AcceptSecurityContext