Modem Dial-up Connection Connecting Error

Morning dear friends,
I am having problem with my Dial up modem connection.
It was working fine and suddenly it stopped working and gave this error message stating that there is an error in connection.
I thought that my connection might be out of credit, so topped up my connection with the credit and then tried to connect it but again I received the same error.

Dialing *99#…
Error 651: The modem (or other connecting device) has reported an error
Then I deleted the connection and made a new connection, through the connection wizard and then again tried to connect the modem, but the same error re-appeared there.
As it shows a redial try after 60 seconds, I let it try the redial after 60 seconds. It tried the redial but failed to connect.
Now please, can anyone tell me why is this error repeating, while I have the credit and connection installed perfectly?
