Hello @VaraPrasad ,
After digging into issue I found that this error seems to be an internal one of oracle (might worth asking them if you have support subscription):
ORA-03146: Invalid buffer length for TTC field
Cause: A corrupt Two-Task Common (TTC) packet was received.
Action: This is a internal protocol error. Contact Oracle Support Services.
Also you could try with different Oracle Driver version which is more mature like: 12.2.01.
Are you able to test those analysis with encryption disabled to see if that’s related?