HTC One T-MO unable to send mms (picture) to AT&T users

[chickynca]

HTC One (T-Mobile) picture messages not received by AT&T users (both iPhone and Android). Tested from my old S3 (tmo) and they received pictures no problem. I have tried different image sizes. I can receive these same user's pictures no problem. No help from T-Mobile tech support.

 

[Almeuit]

I have been having this issue on my Note 3 to.. It has to be something on T-Mobile's side.

Sent from my T-Mobile Note 3 using AC Forums.

 

[jlarkins08]

I think it's at&t really... Cause I can send mms to any carrier but at&t.. If it was t-mobile I wouldn't be able to send at all!

Sent from my HTC One using Tapatalk

 

[chickynca]

Could it possibly be related to an android update since my old galaxy s3 can send mms to AT&T?