My passport can't send or receive MMS

I am using an unlocked passport picked up off ebay (there was a seller selling new passports for 250 a few weeks back). My carrier is ATT.

So far I have tried the following
1) I have tweaked all the possible mms settings in the advanced tab.
2) Went to att and had them set up my sim to show its using a blackberry
3) picked up a new sim

I am out of ideas, everything else on the phone works as intended (I use colbolt, installed an older fb, patch apps to get around google play services).

Has anyone else had this issue? If so, any ideas on how to fix this?

I had problem like your - I reset settings and it's works.

Otherwise - maybe you have have wrong URL MMSC or proxy? Did you check correctly? I don't have carrier in ATT so I can't give you mine.

Might sound silly, but do u have data enabled?

Posted via CB10

My proxy settings are correct, and my data is on, is there a chance its the phone itself (as in I have a lemon?) I can't think of anything else.