I had to rebuild an Exchange 2016 server with smarthost set to the US Comodo server:
mxpool1.us.spamgateway.comodo.com
I’ve sent my destination port from the Exch server to Comodo to use 587 (rebooted). I’ve tried port 25 as well as 465.
Within Exch 2016 I’ve set authentication and TLS. And I’ve tried it without TLS auth - just username and password.
Authentication credentials are same as logging into my Comodo account at:
https://accounts.comodo.com/login and at https://us.antispamgateway.comodo.com/admin/login.zul
Exch logs report:
2018-03-26T04:43:06.900Z,08D592CC6F0B85F2,SMTP,mxpool1.us. spamgateway.comodo.com,-,Messages: 0 Bytes: 0 (Attempting next target)
2018-03-26T04:43:06.901Z,08D592CC6F0B85F3,SMTP,mxpool1.us. spamgateway.comodo.com,,Session Failover; previous session id = 08D592CC6F0B85F2; reason = ProtocolError
2018-03-26T04:43:06.901Z,08D592CC6F0B85F3,SMTP,mxpool1.us. spamgateway.comodo.com,+,SmartHostConnectorDeliver y 056fc4b2-eb3d-426d-8281-c3f0dad5db41;QueueLength=TQ=2;AN=3;.
2018-03-26T04:43:06.987Z,08D592CC6F0B85F3,SMTP,mxpool1.us. spamgateway.comodo.com,>,Established connection to 192.186.179.190
2018-03-26T04:43:07.765Z,08D592CC6F0B85F3,SMTP,mxpool1.us. spamgateway.comodo.com,-,Messages: 0 Bytes: 0 (Attempting next target)
2018-03-26T04:43:07.765Z,08D592CC6F0B85F4,SMTP,mxpool1.us. spamgateway.comodo.com,,Session Failover; previous session id = 08D592CC6F0B85F3; reason = ProtocolError
2018-03-26T04:43:07.765Z,08D592CC6F0B85F4,SMTP,mxpool1.us. spamgateway.comodo.com,+,SmartHostConnectorDeliver y 056fc4b2-eb3d-426d-8281-c3f0dad5db41;QueueLength=TQ=2;AN=3;.
2018-03-26T04:43:07.853Z,08D592CC6F0B85F4,SMTP,mxpool1.us. spamgateway.comodo.com,>,Established connection to 192.186.179.189
2018-03-26T04:43:08.627Z,08D592CC6F0B85F4,SMTP,mxpool1.us. spamgateway.comodo.com,-,Messages: 0 Bytes: 0 (Retry : You have been denied authentication due to possible brute-force attempts;please try again later.)
Comodo tech support has been… slow
Ideas?
Thanks.