In Settings, APN I set it automatically by resetting APN. I deleted all APN under Settings - Network and Internet - SIM card - Accesspoint name. Clicked 3 vertical dots, and did reset to standard settings.
But still i could not send MMS.
Then I tried to set compress mms to 300kB under SMS app, chose burger meny, Settings, Compress MMS, and chose 300kB. And sending worked!
Maybe the provider has limitation sending bigger MMS’es. Auto and other settings there didn’t work for me.
Love the e/OS!