Start here: http://www.mcmaster.com/#timing-belts/=11nt05w
GT2 should fit as well, they are compatible profiles iirc. Just make sure to get the right pitch, as “GT2” comes in a variety of pitches, just like HTD, GT and GT3 do (all compatible). The correct name for the common 2mm pitch belts is “GT2-2M” .
It isn’t alignment. It was working perfectly after I adjusted the belt but has 300 more hours on it. The belts have 1500 hours… Either way I’m replacing them