MMS only working if connected to WiFi

[Topshelf]

I'm having a problem with my MMS messages that I can't solve. I can only send or receive them if I am connected to WiFi. If I'm using cellular data, I only receive a message that the message either could not send, or that it failed to retrieve the message. However, once I connect to a WiFi, I can retry the message and it works perfectly. Strange thing is I can watch it disconnect the WiFi to send/retrieve the MMS over cellular data, so why do I need to be connected to WiFi at all? I'm using an AT&T sim card and everything else works perfectly. Can someone please help me sort this out? I'm using a Samsung S7 Edge if that matters.

Thanks in advance.

[ST-Jean]

Hi Topshelf! My name is Straight Talk Jean. Sorry that you’re having a problem. I will contact you directly with a private message. Thank you.