Edit: Got the problem Wrong
Always had the move and steer option on my right mouse button. The binding has changed to middle mouse (Not sure if I did this accidentally or something reset it) And Will Not Bind to right mouse at all. It’s like it’s pretending the input isn’t there. As far as I can tell it is not a hardware problem.
Is this happening on all characters or just one character? The setting can’t be changed in-game but you can manually change it in the bindings-cache.wtf file. This can be found in this folder:
World of Warcraft\_retail_\WTF\Account\{Account Name}\{Realm Name}\Character Name}
In that file you’ll want to have this line to assign move and steer to the right mouse button:
bind BUTTON2 MOVEANDSTEER
Sorry assumed my problem was something it’s not. I use WASD with A & D for strafe and holding down right click for turning. Quite simply Right Mouse button doesn’t do this the game now. The right mouse button still works for other things in game but not as a focus for my character
Hey Lurindra,
Have we already tested the suggestion by Zhyxen? This may require some custom modification of files to test but it should work.
Keep in mind this may only fix the problem. If an addon or other third party software is changing the keybinds outside of the normal game settings then that software may need to be removed until the vendor can resolve the issue.
Hope this info helps!
This doesn’t seem to work on MacOS. 
You would need to ask for assistance in the Mac Tech Support Forum.