Solved! Go to Solution.
@Kenneth-071: When the time comes, please can you also ensure that you head to Settings > Connections > More Connections Settings > Rich Communications, and toggle this option on. Following this step, open the Messages app > Tap the 3 dots in the top right > Settings > Chat Settings > Chat Features > On.
Well, here we are 9 days later and still getting the same 'Registration Failed' message upon trying again. Samsung really needs to update their messaging app & add the ability to verify your phone number when registering for chat features like in the Google messages app.
I've read in another topic that you have to make sure that the Rich Communications option is turned on @ Settings > Connections > More Connection Settings, however that option isn't available on my device (for some reason).
But that doesn't matter, because I finally managed to re-register RCS/Chat Features on the default Samsung Messages app:
I basically had to install the Google Messages app from the Play Store, then register for chat features with my number on that messaging app, then switch the default messaging app back to Samsung Messages and when prompted to enter my phone number to register for chat features again it eventually registered successfully. Though it took like 4 - 5 tries swapping between Google & Samsung Message apps before it finally worked.
It just seems to me that if Samsung were to add a way of verifying your phone number when registering for chat features that this wouldn't even be an issue.
mines still not working hast worked since I got this device A71 over a year ago & its a great feature, I've tried every solution that's been posted and it's still not working.