- A transport rule is set up that has the Defer the message if rule processing doesn't complete option enabled.
- During text extraction, the scanning process timed out when inspecting the attachment.
- Password-protect the message before you send it.
- Disable the Defer the message if rule processing doesn't complete option in the transport rule. Be aware that this option may be set on any rule in the rules list. For more info about how to modify transport rules in Exchange Online, see Manage transport rules.
Article ID: 2984127 - Last Review: 20 Dec 2016 - Revision: 1