Left Mouse Button No Longer Working

Suddenly during play the left mouse button stopped working. Troubleshooting performed:

Left Mouse Button on the Input screen in Options is greyed out and non-selectable.

Remapped mouse buttons - no change.
Changed USB ports - no change.
Changed mouse - no change.
Uninstalled/reinstalled game - no change.
Ran Verify via Epic - no issues/no change.
Deleted cache files - no change.
Deleted config file - no change.

Problem affects all characters on server.

Game is currently unplayable.