EDITED AFTER SOLVED:
The problem was the Chomp SMS app. This issue never occured on Verizon, but it was a simple settings change in Chomp to fix it:
Settings-MMS-MMS Advanced--MMS Behaviour--make sure this is set to SYSTEM and not LEGACY.
Might be worthwhile to leave the original details below in case anyone else has the same problem:
Can anyone please help? My wife and I switched to XFinity Mobile yesterday and bought 2 Galaxy S8s. Neither of us can recieve a MMS message on either phone. Whether we send to each other,or if others send us a MMS, we never get it. No error or anything when sending a MMS either--it just doesn't seem they're actually sending since the receiver never receives anything. SMS works fine, as does all other data and wifi-related connections. We almost immediatley receive all SMS messages.
I spoke to support, and they had me do a network reset of both phones but it didn't help.
The XFinity entry is there under Mobile Networks-Access Point Names.
I had Verizon for almost 20 years, and never had a problem at my house sending or receiving MMS messages.
Having the same issue here. Started about a week ago.
Every so often is I continue to spam the Picture/MMS Message, it may go through, but only after trying about 15 or more times.
I'd like to point out my Celluar Data Works, I have reset network settings, checked APN information, power cycled, wiped my phone completely, did not restore any contact information or apps and tried it bare bone factory default, and run it in safe mode. Nothing works.