Re: That sometimes happens on smartphones? Do this
Manually set your APN. Not sure how to do it in the stock msging app but I know it can be done in chompSMS (I used to use that after I got tired of GoSMS). Download
APN Utility and use it to back up your APN. If you aren't rooted or have it as a system app then you won't be able to restore but its ok. After you back up, use your fav file manager to read the xml file that will be in the /apn folder and find your apn settings. There will be a few listed, some for 3G, WiFi, maybe 4G, 2G. Just find the ones for 3G and then manually enter them into the msg apps settings.