adop patch fails with error code 255

Symptoms

While applying 12.2.11 patch, adop fails with below error

$ adop phase=apply apply_mode=downtime patches=31856789 restart=yes abandon=no patchtop=/mnt/install_images/oracle/EBS122Patches/EBS12211/12211 workers=16 wait_on_failed_job=yes

Enter the APPS password:
Enter the EBS_SYSTEM password:
Enter the WLSADMIN password:

Validating credentials.

Initializing.
Run Edition context : /dodiapps/prod/prodapps/fs1/inst/apps/PROD_prodapp/appl/admin/PROD_prodapp.xml
Patch edition context: /dodiapps/prod/prodapps/fs2/inst/apps/PROD_prodapp/appl/admin/PROD_prodapp.xml
*******FATAL ERROR*******
PROGRAM : (/dodiapps/prod/prodapps/fs1/EBSapps/appl/ad/12.0.0/bin/adzdoptl.pl)
TIME : Wed May 17 15:14:16 2023
FUNCTION: ADOP::GlobalVars::_GetMandatoryArgs [ Level 1 ]
ERRORMSG: Cannot identify any valid application tier nodes in
ADOP_VALID_NODES table. Ensure AutoConfig has been run on all nodes.


[STATEMENT] Please run adopscanlog utility, using the command

“adopscanlog -latest=yes”

to get the list of the log files along with snippet of the error message corresponding to each log file.


adop exiting with status = 255 (Fail)
prodapp(oracle):/home/oracle
$

Fix:

1. Inconsistency observed in dbhost of Apps context File and DB context File

Application Context File

$ grep -i s_dbhost /dodiapps/prod/prodapps/fs1/inst/apps/PROD_prodapp/appl/admin/PROD_prodapp.xml
<dbhost oa_var=”s_dbhost”>PRODDB</dbhost>
prodapp(oracle):/dodiapps/prod/prodapps/fs1/EBSapps/appl

DB context File

$ grep -i s_dbhost PROD_proddb.xml
<dbhost oa_var=”s_dbhost”>proddb-int</dbhost>
proddb(oracle):/dodiapps/prod/proddb/19c/appsutil

2. Change s_dbhost on DB tier to match with Apps Tier (i.e. proddb).

3. Execute autoconfig on DB tier to ensure it executed successfully.

4. Run the ADZDDMDIAG.SQL script again to verify that all critical ADOP tables are in sync.
SQL> @$AD_TOP/sql/ADZDDMDIAG.sql

5. If any tables show out of sync in 4, Run the ADZDDMFIXER.SQL script to correct the tables that are displayed as not in sync in adzdshowdmdiag.out
SQL> @$AD_TOP/sql/ADZDDMFIXER.sql

6. Run the ADZDDMDIAG.SQL script again to verify that all critical ADOP tables are in sync.
SQL> @$AD_TOP/sql/ADZDDMDIAG.sql

7. Restarted the patch with restart=yes and bandaon=no option.

adop phase=apply apply_mode=downtime patches=31856789 restart=yes abandon=no patchtop=/mnt/install_images/oracle/EBS122Patches/EBS12211/12211 workers=16 wait_on_failed_job=yes