Hi,
Let the users who encounter the issue check this option in Outlook 2013:
FILE -> Options -> Mail -> Save messages.
If the user has selected "Outbox" after "Save to this folder", then the sent emails are saved in the Outbox; Check "Sent Mail" and click OK, then see if the problem persists.
Regards,Melon Chen
Forum Support
Hi,
I suggest you check if there is any rule that makes the sent email stored in the Outbox. Also, check if the problem persists when the affected users use Outlook in Safe Mode:
Press Win + R, type "outlook.exe /safe" in the Run dialog, press Enter.
We may consider the issue is caused by some 3rd-party add-ins if the issue doesn't occur in Safe Mode. Disable the suspicious add-ins to verify which one caused the issue.
As you mentioned it seems that the issue only occurs in Online Mode? Actually the Cached Mode fits most users' needs and it is more recommended, is there any reason you need to use Online Mode only?
Regards,Melon Chen
Forum Support
Hi,
Just checking in to see if the information was helpful. Please let us know if you would like further assistance.
Regards,Melon Chen
Forum Support
Hi,
I'm marking the reply as answer as there has been no update for a couple of days.
If you come back to find it doesn't work for you, please reply to us and unmark the answer.
Regards,Melon Chen
Forum Support