My VTech DS6722-3 Cordless Phone rings once and then disconnects. Why?

Solution:

Your phone may have the Call Block feature activated, which prevents callers from reaching you if they do not provide their phone number with the incoming Caller ID. Your phone rings once. The call then automatically disconnects.
To turn the Call Block feature off for all incoming calls without numbers: Step 1: Press MENU/SELECT on any system handset, when the phone is not in use.
Step 2: Press VOLUME UP or DOWN to choose Call block, then press MENU/SELECT.
Step 3: Press ,b>VOLUME UP or DOWN to choose Calls without numbers, then press MENU/SELECT.
Step 4: Press VOLUME UP or DOWN to choose Unblock, then press MENU/SELECT. You will hear a confirmation tone.

problem solved
more help