Can't Tilt camera angle

Found a fix, it seems that typically it is actually the mouse that is the problem because depending how old your mouse it, the middle button can start having trouble detecting a middle click. The solution for me was to simply get a new mouse. Even though the middle button was working for scrolling, it was not working for clicking, if you are having this issue press down harder on your middle mouse button and see if it will work, it if does work but you had to press really hard than I would suggest replacing your mouse.