ADOP Apply Phase Error: You Must Be In Maintenance Mode To Apply Patches

a.     Verify below entry in tnsnames.ora on RUN FS and PATCH FS in R12.2

 TESTCDB =

 (DESCRIPTION =

  (ADDRESS = (PROTOCOL=tcp)(HOST=apdb001.myorg.com)(PORT=1521))

  (CONNECT_DATA = (SERVICE_NAME=ebs_TESTPDB) (INSTANCE_NAME=TESTCDB))

 )

 b.    Verify local_listener parameter configured in 19c for R12.2 as

       SQL> alter system set local_listener=TESTCDB.myorg.com:1521 scope=both

 c.    Verify service_names parameter in 19c and must be set to CDB  as

         SQL > show parameter service
                   service_names  TESTCDB