Mms with straight talk on att topic

Ok I have been reading for days
I have a note 3 att branded locked
I am using straight talk
I can not get or send a mms message (picture)
When I try to get one I get a download box that will never complete
I have verified the settings on the straight talk Web site and the application
I have tried the ideas I have seen posted but I still can't get one.

Someone suggested it could be the sim card?
I have even turned off lte and tried then turned it on and tried.