Troubleshooting Tip: FortiMail in gateway-mode stops to forward emails.

[Mono_FTNT]

Description
If a FortiMail in Gateway-Mode stops forwarding emails and the following error message is observed on the console:

- 01.15-01:03:02 Critial error, cmf_lock.c, __cmdb_rwlock_lock, 252, semid=32769, pid=14489, errno=22 timeout=0 exiting...

This is an indication that the FortiMail has run out of memory and cannot process SMTP requests

Solution
Reducing the number of SMTP connections will reduce the risk of the memory issue and allow the FortiMail to forward emails.

config system mailserver
  set smtp-max-connections 256  <= here
end

The recommended value is 100, but you may need to adjust this to suit your FortiMail model

If this error occurs in a FortiMail 32-bit image, it is reccomenced you migrate to the 64-bit version which can manage more memory.