There are several reasons why you might want to undo message blocking:

If you are on a family plan, the account holder may have enabled restrictions that prevent you from messaging. This is common on plans designed for children (e.g., T-Mobile FamilyMode, Verizon Smart Family).

To undo message blocking on WhatsApp:

If you are unable to receive texts or calls from a specific person, you may have inadvertently added them to your blocked list.

Apple centralizes its blocking system. When you unblock someone for texts, it also unblocks them for FaceTime and phone calls. Open . Scroll down and tap Messages . Tap Blocked Contacts . Swipe left on the name or number. Tap Unblock . How to Undo Message Blocking on Android