Quick Fixes:

• Reboot: A simple restart often clears temporary glitches. Try it first!
• Airplane Mode: Ensure it's off. This mode blocks all signals, including texts.
• Check Network: Make sure you have a cellular signal. If weak, try moving to a better location.
• SIM Card: Check if it's properly inserted. Remove and reinsert it, ensuring the gold chip faces down.

Deeper Dives:

• Network Settings Reset: This reconfigures your network connections. On Android, it's under "Settings > System > Reset options".
• Clear App Cache (Android): Go to "Settings > Apps > Messages > Storage > Clear cache". This frees up space and resolves app glitches.
• Check Blocked Contacts: Did you accidentally block the sender? Unblock them in your messaging app's settings.
• Storage Space: If your phone's storage is full, it can affect apps like messaging. Free up space by deleting unnecessary files.
• Carrier Issue: Contact your carrier to check for network outages or service issues in your area.

Bonus Tips:

• Update Software: Make sure your phone and messaging app are up-to-date.
• Third-Party Apps: Certain battery-saving or security apps can interfere with messaging. Try disabling them temporarily.
• Factory Reset (Last Resort): This erases everything on your phone. Back up your data first and proceed with caution.

If these solutions don't work, contacting your phone manufacturer or carrier for further assistance might be necessary.