Hi Genny. Checked all of the camera controls. Everything appears unlocked. Even selected them just in case and tried 'unlocking' them from the dropdown menu. New cameras have the same issue.
Only...

Hi all.
I recently imported an FBX and the viewport is only rotating in 2 axes.
I tried resetting Maya's prefs but it seems to be in the file itself.
Holding alt + LMB and dragging left and right...