Check Spam
Open Spam in the affected mailbox when an expected message is missing. Treat suspicious links and attachments cautiously, even if a message appears to come from a familiar sender.
If a message is legitimate, use the available move or not-spam action to return it to a suitable folder. Moving one message does not guarantee every future message will be classified the same way.
Check Bin
Deleted messages may appear in Bin while they remain retained. Use the available move control to restore a retained message to another folder.
Permanent deletion and an empty-folder action can remove retained messages. Read the confirmation carefully. Do not assume support can recover permanently removed content.
If delivery is missing
Ask the sender to check their delivery report and confirm the exact address. Check the correct mailbox and any rules or folder actions you use.
For business domains, the owner should verify receiving readiness and DNS configuration. Do not repeatedly delete or empty folders while investigating missing messages.