The issue is likely caused by an Outlook add-in hanging during send. Disable the add-in by starting classic Outlook in safe mode and then turning off the problematic add-in.
Follow these steps:
- Close Outlook.
- Start Outlook in safe mode so all add-ins are disabled:
- Press the Windows key.
- Type
outlook.exe /safeand press Enter.
- In safe mode, try sending a test email.
- If the email sends successfully, an add-in is causing the problem.
- Disable add-ins in normal Outlook:
- Close Outlook and reopen it normally.
- Select File > Options > Add-ins.
- At the bottom, next to Manage, select COM Add-ins and choose Go.
- Clear the check boxes for all add-ins (especially the one shown in the message) and select OK.
- Restart Outlook and test sending again.
- If sending now works, re-enable add-ins one at a time, restarting Outlook and testing after each, until the failing add-in is identified. Leave that add-in disabled.
If emails still will not send after disabling add-ins, repair the Outlook profile and program as additional steps:
- Repair the Outlook profile using the steps in Fix your Outlook email connection by repairing your profile.
- If needed, repair the Office installation using Repair an Office application.
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