Problem with MMS since update to android pie

First - this is NOT an Xfinity problem.  I had (yes, "had" - we'll get to that) the problem and it was an issue on any wifi connection - home, work (not Xfinity), my brother's house (not Xfinity)...  In addition,  I have a Samsung S9+ and my wife has an S9.  We got them at the same time.  Hers has never had this problem.  We both use Messages from Google LLC instead of Messages from Samsung.  Oddly, we have different versions listed - hers is newer - so I was trying to get that one to load on my phone, with no luck.  However, uninstall and reinstall of the application resolved my issue.  I had gone through all settings and found no differences, but I may have missed something.  I also had the problem with Messages from Samsung and now no longer, so reinstalling the Google app changed something that affected both apps.

For those interested, here are the versions.  I'm going to contact Google about that.  

5.4.087 Roper_RC15  1/29/2020  mine
5.7.097 Unicorn_RC09  3/25/2020  hers

MMS seemed to be working fine for me this past weekend (after months of same problem).  I didn't notice any updates, so not sure if just a fluke or something was fixed.  But I didn't have to turn WiFi off to send mms messages.  Will continue to monitor, but fingers crossed.  (Samsung S10+)

I just tried to send myself a pic with wifi on and no luck. I did have a pic go through on both google messaging and Samsung messaging the other night. I got all excited but the next morning, I was back to it not working again....

I have the same version as your wife. I'm not able to send pics without turning off wifi with either it or the Samsung messaging app.

I didn't mean that it was an Xfinity internet problem...I meant an Xfinity mobile problem.

When I got my phone, they sent me a new SIM card. They were unable to transfer my # to the new SIM for some reason so they told me to put the old SIM in the new phone. That meant they had 2 SIM cards registered to me so I have 2 lines listed on my account but I only have one phone. I've been trying to get that straightened out for over a month. Every time I call, they escalate me to a higher tier, I'm assured the issue will be fixed and they'll follow up with it and call me back to verify that. No one calls me back, I call back and we start the whole thing again. I don't have a whole lot of faith when Xfinity says "it's not us, it's Samsung!" 

And apparently, mine has stopped working again, too.  Frustrating issue. 

It's been working fine for me for about a week now, but agree that it is a bit slower than expected.  As long as it's working with any manual intervention, I'm happy!  Fingers crossed.

Currently working  but don't know how long that will last. Seems pretty sporadic and very slow, about 10 seconds to send a picture. Turning the wifi off sends within a couple seconds and the Macrodroid turns it back on pretty much instantaneously so we'll see.

Isn't that funny....Textra didn't work for me when I tried it. I ended up installing macroDroid which will automatically turn my wifi back on if I have to turn it off to send a mms. For the most part now, I don't have to turn off the wifi to send anything, whether that was an update on Samsung's, Android's or Xfinity's part I don't know. Once in a blue moon I'll get something that doesn't go through. Odd. For what you pay now for a phone and service, the things should perform flawlessly.

My Samsung Galaxy A50 is finally able to send MMS without turning off the wifi.

Nice job describing symptoms and workaround, people!   🙂     Trying different messaging apps is a great way to test/mitigate/workaround these sorts of android MMS/texting problems.    Remember to try the default google "blue icon" messaging app too as well as the manufacturer default.   Try that blue default google messaging app especially when the manufacturer default messaging app keeps tanking...