"Error downloading MMS..." in group messages with non-Signal users.

[dscotese]

• I have searched open and closed issues for duplicates
• I am submitting a bug report for existing functionality that does not work as intended
• I have read https://github.com/signalapp/Signal-Android/wiki/Submitting-useful-bug-reports
• This isn't a feature request or a discussion topic

---

Bug description

With increasing frequency, groups that contain non-Signal users don't show messages but instead show "Error Downloading MMS message, tap to retry." This is actually a duplicate of #6234, but that one is closed and not resolved.

Steps to reproduce

• Create a group that contains contacts who are not using Signal.
• wait for someone to send a message to the group.
• If you get the message as usual, then keep the conversation alive until you get the error.

Actual result: I see "Error Downloading MMS message, tap to retry." in the group message.
Expected result: The message sent by my contact should appear.

I was able to get one recent message from a non-Signal user after enabling "'WiFi Calling' compatibility mode," AND restarting my phone, though I don't use WiFi calling.

Device info

Device: Samsung Galaxy S7
Android version: 8.0.0
Signal version: 4.49.18

Link to debug log

https://debuglogs.org/1065bd97a8eb1f39bbcedda5f91b5a74e0ff562c924e284b33ca90275d829c36

[Tursko]

This issue has already been created. Please make sure you check before creating an issue - #9173

"I have searched open and closed issues for duplicates"

Please Link your debug log in the issue linked.

[dscotese]

I thought so too, but my phone receives MMS from individual non-Signal users just fine. It's only the group messages that present a problem.

[Tursko]

It's probably related to the same issue though. It still seems like a duplicate.

[dscotese]

I agree it's probably related. I was thinking that Apple might have tweaked their implementation of the MMS protocol in a legal (according to the spec) but peculiar way in an effort to discredit iOS competitors (Android) who aren't careful about implementing it. The reason I wanted to create a separate issue is that it would be a shame for Signal devs to examine the code to solve only one of these two intimately related problems. I will add my debug log to the other issue. Thanks for suggesting that.

[Tursko]

According to that other thread, the issue seems to be isolated to ATT users (and other sub-carriers). Also its only when using SMS/MMS through Signal. No one has any issues getting MMS from the default Google Messages app. So it seems like a Signal related issue.

But awesome, hopefully the issue gets fixed.

[madfusker]

Same annoying issue on ATT SSGS9 on Android 8. :/

[greyson-signal]

Closing as a duplicate of #9173