Comment Comment by kl343 If the sender is using Exchange Online, this might explain why OOO replies would be marked as spam more frequently:https://github.com/MicrosoftDocs/OfficeDocs-Support/blob/pub..."By design, Exchange Online Protection uses the high risk delivery pool (HRDP) to send OOF replies, because OOF replies are lower-priority messages." parent kl343 4 years ago
https://github.com/MicrosoftDocs/OfficeDocs-Support/blob/pub...
"By design, Exchange Online Protection uses the high risk delivery pool (HRDP) to send OOF replies, because OOF replies are lower-priority messages."