boss may solution po ba dtohindi stable ang signal in your location or may faulty sa signal from your ISP (SMART) or in your device
galaxy tab 4 sm-t231 po .. yan po gamit koano gamit mong device for that sim?

salamat po. try ko mamayaTry this:
-go to playstore and download "ccleaner" and clean your phone cache and junk files (use wifi if the mobile data has problem )
-go to settings>battery> uncheck CPU power saving mode (if available)
-go to developer options and check Force use of GPU Rendering (If Developer option is not present just tap the about phone in settings 5X
-set your Network Mode 4G or 3G only
-[check] mobile data service preferred in mobile network settings
-check your reset to default your APN
-then turn off your phone for about 5mins. and then turn it on
-Turn on data connection (don not browse yet or use internet just observe till the data indicator is stable
-the you may browse or use internet now.....
Hope this works