No MMS after Cyan update on AT&T (Unlocked Phone)

[NutmegState]

I have a unlocked 920 that is of type Carrier: IT Country Variant. This should not matter considering this did not seem to matter for all prior system updates.

Never had an issue until Cyan update. Now I can no longer send or receive MMS Messages.

Access Point is set to AT&T and active (proxy.mobile.att.net, MMSC Address: http://mmsc.mobile.att.net, No username or password shown

Data Connection is on. I can surf the web, get WhatsApp messages, receive emails and play videos.
I can send and receive text messages

Basically, everything except send and receive MMS.

It is an unlocked phone, do I need to do something special? Is there something else I need to turn on?

 

[Muessig]

What happens when you try to send an MMS? With some carriers you have to make sure this ability is enabled by your carrier.

 

[NutmegState]

I spent hours at the AT&T store, everything in my account says MMS is enabled, but I cannot send nor receive. I have not called tech support, but I dread getting on the phone with them. It has never been a fruitful phone call