Outbound MMS Messages not arriving to destination

[adventure-tense]

Checklist

• I can reproduce the bug with the latest version given here.
• I made sure that there are no existing issues - open or closed - to which I could contribute my information.
• I made sure that there are no existing discussions - open or closed - to which I could contribute my information.
• I have read the FAQs inside the app (Menu -> About -> FAQs) and my problem isn't listed.
• I have taken the time to fill in all the required details. I understand that the bug report will be dismissed otherwise.
• This issue contains only one bug.
• I have read and understood the contribution guidelines.

Affected app version

1.0.1

Affected Android/Custom ROM version

GrapheneOS Version 15

Affected device model

Pixel 8 Pro

How did you install the app?

F-Droid / IzzyOnDroid

Steps to reproduce the bug

1. Install Fossify SMS Messenger App, and Designate as default. Agree to permissions.
2. Open Fossify Messenger app (as default app)
3. Click on "+" in app to attach photo.
4. Click on send MMS.
5. Receive confirmation that it was sent.
6. Verify with recipient that they did not receive my photo.
7. Text sent by SMS does work correctly.
8. This bug will happen 99% of the time.

Expected behavior

Recipient should receive photos (or other compatible attachment).

Actual behavior

MMS messages "appear" to send correctly, but are not received by recipient.

Text messages sent by SMS are being recieved as normal.

Screenshots/Screen recordings

No response

Additional information

This bug is only appearing in the Fossify version of this app (1.0 and 1.01). The issue is not present in the Simple SMS Messenger (5.19.3), which works normally, immediately after installation. The native GrapheneOS SMS Messenger also works correctly when set as default.

[Aga-C]

Please try to set the attachment size limit in Settings to 300 kB and let us know if MMS messages are received.

[adventure-tense]

I made the change in settings.

I duplicated the test five times. I did get an image to send and receive on the first attempt. But the next four attempts did not get received.

I duplicated the test in Simply SMS Messenger and it worked all five times. I then increased the size to 2MB and those images also were received.

[adventure-tense]

I duplicated the test in Fossify SMS Messenger, again five times, reducing attached image size to 100kb.

Unfortunately, none of the images were recieved.

[pikurasa]

I had a similar issue, but for me changing to 300kb resolved it. (Just "FYI".)

[puutelias]

Also unable to send any MMS messages from my app (Android 15, Oneplus 12; App version 1.1.4). Changing outgoing MMS size in the settings does not change this behaviour. However, all attempts do give an error "Not sent. Tap to retry"

Edit: After manually correcting default APN settings, I then had to reduce my outgoing size to 600kB to fix the sending issue.