Dial-up Connection Error 623 – The system could not find the phone book entry for this connection
Dial-up connection error 623 is caused when Remote Access Connection (RAS) phone book is not found. Dial-up connection entries are stored in below file,
c:\Users\All Users\Microsoft\Network\Connections\Pbk\rasphone.pbk
If the RAS connection is made with an entry that is not in the above phone book, dial-up connection error 623 is observed.
With cellular modems, when the SIM card is not present or locked, dial-up error 777 can happen. Use AT Command Tester tool to check the status of the SIM Card.
