Last week ran through the problem like Microsoft Exchange Transport Service wasn’t starting, rebooted the server couple of times but still it was stopping immediately after starting the service.
Went through the application log and found 16023 which says Microsoft Exchange couldn’t start transport agents. The Microsoft Exchange Transport service will be stopped. Exception details: No valid agents.config file was found in ‘C:\Program files\Microsoft\Exchsrvr\Transport Roles\Shared\agents.config’. The default configuration for transport agents can be recovered by running ‘scripts\ReinstallDefaultTransportAgents.ps1’.
As event itself says we ran the ReinstallDefaultTransportAgents.ps1 from the scripts which is located in “C:\Program files\Microsoft\Exchsrvr\Scripts” (default location) we were able to start the Microsoft Exchange Transport service successfully. Hope this would help if you are in same situation.