2.)Always make sure the phones up to date on the latest firmware.
3.)The next step is to go to the dialer ##72786# that forces the phone to reactivate.
4.)Next step go back to the dialer and dial ##3282#
4.2)Go to edit
4.3)Then type 000000
4.4)Then go to LTE
4.5)Then go to band 41 that is enabled and uncheck to disable.
4.6)Then go to band 25 that is enabled and uncheck to disable.
4.7)Then go to band 41PCII that is enabled and uncheck to disable.
5.)Reboot the phone don't expect full LTE service yet there are still some more steps...
6.)Go to settings find VOLTE and enable. Search VOLTE in the search bar to enable it.Swipe right on the button to turn it on. New icon will pop up at the top of the phone if done correctly.
7.)Then go back to the dialer and type ##3282#
7.2)Go to edit
7.3)Then type 000000 again
7.4)Then LTE again
7.5)Then go to band priority
7.6 & 7.7)Set both bands 41 and 25 to the bottom of the list by typing the number 17 on band 25 and 18 on band 41 and that pushes them down the list. Make sure band 26 is set to 1 on the priority list.
7.8)Then turn off your phone and turn it back on.
This fix is broken from a network reset or ##72786# update or Samsung software update. So reapply the fix after each update or network reset