If you're having issues with apps like Teams, Skype For Business, etc. then you may need to reset your user account permissions so the apps can communicate properly with the permissions folder which houses the settings for that. Here's how to do so:

  1. From the Finder menu bar, choose Go > Home. Right click on your home folder (labeled with your first name.last name) and choose Get Info. An Info window for your home folder opens.
  2. OR, you may have your home folder in your Favorites in the navigation pane on the left, right click it there and choose Get Info. An Info window for your home folder opens. 
  3.  
  4. If the Sharing & Permissions section at the bottom of the window isn't open, click the triangle  in that section to open it.
  5. If the lock at the bottom of the window is closed lock, click the lock and enter an administrator name and password to unlock it.
  6. Click your user account (first.last) so it is highlighted, and then click the action menu , then choose Make "first.last (Me)" the owner. If this section is greyed out, then proceed to step 9.
  7. Next, click  again and choose Apply to enclosed items.
  8. Click OK on the permissions pop up window. A progress bar appears at the top of the window, and will disappear once the action is completed. When done, open the Terminal application, which is in Applications/Utilities.
  9. Copy/paste the following command into the Terminal command prompt, then hit Return.  
  10.            diskutil resetUserPermissions / `id -u`
  11. You will see a sort of progress bar within the Terminal window, and this process may take a few minutes. When it's done, you'll see something like this:
  12. When this action is completed, restart your computer.