After upgrade to 21.0, windows agent is down and won't start

Products

• CA Automic Workload Automation - Automation Engine
• CA Automic One Automation

Issue/Introduction

A windows agent is down and won't start (affecting multiple critical production jobs)

20230331/120914.478 - U02000134 Thread 'TCP-Thread' started.
20230331/120914.478 -           Wrong configuration, bad definition of parameter 'port' in section [TCP/IP] of the configuration file.
20230331/120914.478 - U02000302 Agent shutdown has been initiated with return code '69'.
20230331/120914.478 - U02000135 Thread 'TCP-Thread' ended.
20230331/120914.478 -           Waiting for File Transfer threads ...
20230331/120914.478 - U02000041 Shutdown Agent 'WIN01'.

Environment

Release : 21.0.5

Resolution

The port = setting in the agent ini file was blank and it was also using the old 12.3 ini file
Update the ini file to use the 21.0 agent ini file.  Then in client 0 renew transfer key and cleared out agent's security folder