Hi,
Troubleshooting Steps:
Restart your phone: A simple restart can resolve many temporary glitches.
Check your signal: Ensure you have a good cellular signal.
Clear the messaging app's cache and data: Go to Settings > Apps > Messages > Storage and tap "Clear Cache" and "Clear Data".
Reset network settings: Go to Settings > General Management > Reset > Reset Network Settings.
Verify the message center number: In your messaging app, go to Settings > More settings > Text messages > Message center and enter the correct number for your carrier.
Check for software updates: Go to Settings > Software update > Download and install.
Check for blocked contacts: In the Phone app, go to Settings > Block numbers and make sure the contact you're having trouble with is not blocked.
Consider RCS: If you're using RCS, try toggling it off and on, or switching to SMS only.
Contact your carrier: If the problem persists, contact your mobile carrier to check for any network issues or restrictions on your account.
