I've been experiencing a weird issue since I upgraded from v12 to v14. My MX servers (simple exim based machines) pass all the inbound mail traffic to my SmarterMail server. They were never configured as anything radical, just whitelisted on the SmarterMail box to keep from getting throttled. Ever since I upgraded to v14 my MX servers sometimes get kicked from SMTP connections with the error "Remote host mailserver.xxxxxxxxxx.com [xx.xxx.xx.xxx] closed connection in response to sending data block"
These messages get queued on the exim machine and most never make it out until I manually log onto the server and force the queue out with 'exim -qff'
I went as far as to add the MX servers as inbound gateways to see if that would help and the problem persists. This is queuing hundreds of emails that should be passed no matter what.
Any help would be greatly appreciated. Thank you.