Sent mail sticks in the outbox in Outlook 2016

Ed Eckenstein
Ed Eckenstein used Ask the Experts™
In Outlook 2016/365, mail gets stuck in the outbox on one particular computer. This does work fine if we send mail from this account a different computer. Sometimes closing Outlook causes it to be sent but lately that doesn't work either. I delete the PST file and restarted Outlook so got rebuilt. That worked for about 1 day.

Any ideas would be appreciated.
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MontoyaProcess Improvement Mgr

Are there any plugins/extension in Outlook?
Did you do an office online repair?

My first step would be to disable any  add-ons. If that doesn't work, I would do the online repair option.

Let me know how far that goes...
Hardware Tester and Debugger
Hi there! :)

Open Outlook in Safe mode and disable all add-ins besides the Exchange Server add-ins to test again. One add-in that can cause this is the iCloud Outlook add-in. You also need to ensure the option to “Send immediately when connected” is checked in settings.

Open Outlook in Safe Mode:
Disabling Add-ins:
“Send immediately when connected” option:
Brian BEE Topic Advisor, Independant Technology Professional

Did you mean PST or OST file? If you haven't deleted their OST file yet, try that as well. Also turn off the antivirus program temporarily.
I'm with Brian, I'm curious how you would even use a PST with Exchange, unless you are thinking of as an archive.


Thanks to all. It's definitely a plugin issue. Now I need to figure out which one.

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