MMS not working on Factory Unlocked iPhone 11 Pro Max with Total Wireless. Worked on T-Mobile & Tello

Hello.

I purchased an 11 Pro Max factory unlocked in October 2019. I used T-Mobile Prepaid as my carrier. All features worked great.

In January 2021, I switched to Tello, the Sprint option. Again, all features working great, but the data coverage was spotty where I live. So I changed to the Tello T-Mobile option. I found out later that the group messaging, WiFi calling and Visual Voicemail were not available on the T-Mobile option.

I then realized that MMS messaging was not working and so I couldn't send messages to people with Android phones, which is my whole immediate family. Tello was not able to solve the issue.

I ported my number to Total Wireless. The porting process was flawless, and everything works great except I can't send MMS messages: I can send a text only message to folks with Androids, but can't include a photo and can't do group messaging, even those that option exists in settings and is turned on.

I have spent about 2 hours on the phone with TW in the last 24 hours, and we have tried everything. Updating carrier settings, making sure all the right settings are on, and it is still not working. TW does have all the options that Tello did not, and all my settings are correct.

When I attempt to send a picture/MMS message to an Android user, it gives me the read exclamation mark and says "Not Delivered." It does not give me the option to send as SMS message, like it used to when I had T-Mobile.

The highest level of escalation at TW told me:

• iPhones can't send MMS messages to Androids, only text messages
• iMessage needs to be off to send a text message.
• These two statements do no appear to be correct, as I did it with T-Mobile and Tello (Sprint) just fine.
• When I asked what my options were, they told me to "contact Apple."

There is no option to change the APN--the fields are not available and when you send a request to update the APN option to their automated texting support, it says, "Your data settings should be configured properly. Turn your devices off and back on and try again. If you continue to experience issue, contact Support." I did that and they were unable to help me.

Please, what suggestions might you have for next steps?

1. I am pretty good at trouble shooting issues like this and was able to do everything TW did. I also tried Googling a bit to no avail.
2. Is there any reason to consider resetting the phone to factory settings and then restoring to backup?
3. Any other ideas are greatly appreciated!

Thank you.