Ac belt falling off

[xrevx1]

2007 GMC YUKON DENALI. Ac belt came off. Figured it was belt and tensioner. Replaced both with items purchased at O'Reillys. Belt is continuing to fall off. Any ideas?

 

[OR VietVet]

Need to check the alignment of the belt and see if running at an angle or something is hitting the belt or something locking up.