Can't send MMS on T-Mobile after Denim upgrade

[IMarshal]

I'm using an unlocked AT&T-branded Lumia 830 on the T-Mobile network. Things generally work well.

This started happening after the recent Denim and 8.1u2 upgrade. Prior to that, I was able to send MMS texts containing images.

After the upgrade, I can still send normal texts just fine, but when I try to send an image, it times out after a while and tells me it "can't send message".

I'm using the following MMS APN settings:

APN: fast.t-mobile.com
MMSC: mms.msg.eng.t-mobile.com/mms/wapenc
MMSC port: 80

I've tried using epc.tmobile.com instead of fast. I've tried disabling the "Use 4G LTE cellular data for phone calls, text messages and other communications" toggle switch. Neither of these settings change the "can't send message" error.

The only thing that does seem make a difference is deleting the manual MMS APN entirely. When I do that, I seem to be able to send MMS messages. However, the recipient doesn't see either the media content or any accompanying text.

Does anyone have this working?

Thanks.

 

[Camaroon]

I'm in the same boat as well. Upgraded to new Windows 10 mobile build on my 925 yesterday and data and MMS wasn't working. I manually input the settings you have above and data and receiving MMS works now, I just can't send MMS. Hopefully someone might be able to help!

 

[Camaroon]

I was playing around with this all day yesterday, finding all sorts of settings online, and putting them in to the Access Point "app" and in other places as well. Turns out I had the URL wrong. I had http://mms.msg.end.fast.t-mobile.com/mms....I took out the "fast." part, did not include any port number or anything since T-Mobile's site does mention needing it, rebooted the phone, and I could send MMS messages fine. Also authentication type should be "None". Literally everything is blank or none except the APN and the MMSC URL. I know I'm on a different OS than you but hopefully this helps!