When you are in Server Settings > Mail > Undelivered Mail you select an email to respool,
does the email message have the new email server or old email server mentioned for "Server:" section?
Thanks for the reply! The server name is the same, the entire contents of the .cfmail file generated is the same as the ones that are going out correctly. The only settings change was TLS, which doesn't appear to be stored in the file. Does the server store any information about the files by ID somewhere?
In Mail Logging Settings :
Tick Log all mail messages sent by ColdFusion
Respool an email
Does Debugging & Logging > Log Files > mail log provide any useful detail?
Nothing. Not 1 line even debugging.