Environment
Retain 3.x/4.x
Situation
We migrated to a different email system and now we can't forward emails and get Unknown SMTP host errors.
Resolution
The SMTP settings need to be updated so Retain will connect to the new SMTP server for forwarding or restoring email messages.
This is found under the Communications tab in Server Configuration under the Notification section.
Update those setting and Test the connection. If it is successful you will be able to forward messages successfully again.
Additional Information
This article was originally published in the GWAVA knowledgebase as article ID 2804.