If you’re using an Android phone, try these steps:
– Open Messages by Google-
– Tap the 3 dots in the top right corner
– Tap Settings
– Tap Advanced
– Make sure Auto-download MMS is toggled right, it will turn blue
– Make sure Auto-download MMS when roaming is toggled right, it will turn blue
Most major iPhone carriers are set up so that this isn’t a problem. All MMS messages are set to automatically download by default.