MMS Trouble

[Chiliqueen29]

I started having “mms” trouble with an unlocked Sony Xperia and Straight Talk as my service provider. For 1 year I had not had trouble then I had 3 months of problems with no answers; now it’s like an infection. I can’t find answers to the issue of mms messages that won’t open. Many open but then some don’t. I have talked to tech departments, researched blogs and taken the phone to a repair shop - no success.
I purchased a newer Sony and tried a new service provider - nothing changed so I returned it; now
I am trying a SamsungGalaxy 50 thinking that the Sony Xperia was the common thread in this mms trouble.
I like the Samsung, but the same thing is happening with the same service provider. I receive blue “download buttons” that won’t download. Occasionally the button will appear and then download, and sometimes I have no issue. HELP me understand this. I cannot possibly be the only one with this issue.
I have checked settings and APN’s.

 

[Hadron]

Unfortunately that's not a vast amount of information to go on. Is there any pattern to which ones work and which do not, e.g. who is sending them? It could be the provider, or it could perhaps be a problem of message sizes (different networks can have different limits, and I'm not sure what happens when someone sends a message that's OK on their network but above the limit on yours).

To be honest it is several years since I sent or received an MMS: nobody I know uses them (most UK providers charge heavily for them, though SMS are essentially free, so most people use WhatsApp or similar instead).