iPhone: Settings > General > Transfer or Reset iPhone > Reset > Reset Network Settings.
Before diving into advanced settings, try these quick, common fixes: new viral mms name fix
Tap and then select Show All under "Apps Using iCloud". Find Contacts and toggle the switch Off . When prompted, select Keep on My iPhone . Turn the switch back On and select Merge . 2. Force Close and Restart the Messages App iPhone: Settings > General > Transfer or Reset