ORA-12638/ ORA-28545 / ORA-04052 on Windows while accessing DBLINK - 19c Database

 

Accessing DBLINK over 19c [ patchset 19.10 onwards ] gives ORA-12638/ ORA-04052 / ORA-28545
[Warning] ORA-24344: success with compilation error 
ORA-04052: error occurred when looking up remote object 
 ORA-00604: error occurred at recursive SQL level 1 
 ORA-28545: error diagnosed by Net8 when connecting to an agent 
 Unable to retrieve text of NETWORK/NCR messag
 (8: 0)

Fix : - 

In sqlnet.ora file add the paratemeter 
SQLNET.NO_NTLM=FALSE
If you are using gateway, add this parameter on the gateway server sqlnet.ora file too.
Or possibly on all clients where you are unable to access dblink.

NTLM is the Windows Networks LAN Manager authentication service. Access to it has been disabled by default due to a security fix. So NO_NTLM=TRUE is now the standard from 19.10.0 on for Windows systems.