Hey - What network are you with - Please navigate to Settings > Tap More... (under Wireless & Networks) > tap Mobile Mobile Networks > tap APN > tap MMS > ...from you can either
- Simply select the MMS name under the prefered carrier name if more than one service provider appears.
- Create a new APN by entering the values here manually if there is no existing MMS access point (I could give you the values if I new your carrier or network service provider)
- Modify the existing name by editing the values there under in case they have been modified in by mistake.
You can comment below to advise on the model number you have.