If you have enabled Windows Server Protection (Defender) with Attack Surface Reduction (ASR), you might run in a problem that the Cameyo file dialog gets blocked (in Office applications)

To overcome this problem you have to disable the related ASR rule in Windows Server Protection by running the following 

PowerShell command with elevated privileges:

Add-MpPreference -AttackSurfaceReductionRules_Ids D4F940AB-401B-4EfC-AADC-AD5F3C50688A -AttackSurfaceReductionRules_Actions Disabled

More ASR rules here: