I am seeing that some messages in my Quarantine+ are failing to send due to a SpamHero IP address that is "not allowed to send mail from" the sender's domain. What do I do?
If you are not able to turn of the SPF filter on your mail host, to resolve this issue you will need to turn on the SPF Workaround feature. To do so, log into your SpamHero Control Panel, then click Settings > filtering policies
Then scroll down until you see the "SPF Workaround" option. Check the box, then click Update: