iPhone 3GS can't send MMS to one person?

[Eleni]

This is a weird problem. I'm running a 3g (3.1.2) on T-Mobile, I can send pictures and receive them to and from both T-Mobile and AT&T users. Everything works fine, basically.

Now this is where it gets weird. My boyfriend has a 3GS (3.1.3) on AT&T and can receive pictures from me, but he cannot send them to me. It always gives him the red exclamation point failure after stopping at 95%. He can send pictures to anyone else on other carriers, including T-Mobile. Has anyone heard of anything like this before?

His phone is completely unmodded, not jailbroken, nothing.

EDIT: So we managed to fix it. He had my number saved as "iPhone" in his address book. I guess since I am on T-Mobile and not AT&T, whatever setting a number to "iPhone" does in the phone/on the server was unable to work correctly, prohibiting the messages from sending. When he changed my number to "mobile" his phone sent the pictures right away.

Very weird glitch.

Also, he still cannot send them by clicking the camera icon while in our conversation and selecting/taking a picture from there, it still fails. In order for the picture to send, he has to send it from the options while looking at the picture in his album, or he has to compose a new message and attach the picture from there. Weird, but at least he can send the pictures in some way!

[Imahottguy]

Just to clarify, he can send pics to other T-Mobile customers? I'm wondering if the photo files are too large? I'm not sure. Perhaps if you can tweak the MMS config to allow larger files?

[Eleni]

He has no issue sending them to other t-mobile customers, and they have no problem receiving them. I also have received mms from other AT&T 3gs users with no issue, so it's really bizarre.

EDIT: It's fixed! He had my number saved as "iPhone" in his address book, and when he changed it to "mobile" the pictures were actually able to send. I guess AT&T/the iPhone send things differently from one iPhone to another than to any other phone. Because I am on T-Mobile and not AT&T, it must not have been able to read my phone as an "iPhone."