The issue might be related to the file "officebackgroundtaskhandler.exe".
You can locate it under C:\Program Files (x86)\Microsoft Office\root\Office16\officebackgroundtaskhandler.exe.
Check event logs on your system and chances are this is the case.
Try disabling this and see if the issue persistes. Else enable it again.
To disable it follow below steps:
1. Press Windows-key, type "Task Scheduler".
2. Follow Task Scheduler > Task Scheduler Library > Microsoft > Office
3. Locate OfficeBackgroundTaskHandlerRegistration.
4. Right-click on the task and select disable.