How do I Make app compatible with phone

For some reason the first time I uploaded my app to the Android Market I was able to download it to my phone, but after I made some changes, re-uploaded, and published it to the market, now it's saying my phone (Samsung) in incompatible.

Is there anything I could have done to cause this?

WEEKS on an app that I can't even get on my own phone???

Thank you in advance for your help.

Ok what I've realized so far is that on the Play Store it is still recognizing my OLD phone from 3 years ago. I was able to download my game by going directly there with my phone, but If I try to see it on my PC it shows my old phone as the recognized phone.

Anyone know of a fix for that?

I tried this:

Go into "Settings > Apps > All > Google Play Store > Force Stop > Clear data > Restart phone > Open Google Play > Accept Terms."

But it's still doing the same. I haven't had that phone in years so it could be something associated with the particular email address

Thank you