No carrier can mean several things.
No phone line connection to the local modem.
To fix, startby checking all your cable connections. If all connections seem okay, check the number you've told Robot/ALERT to dial. Is this number correct? Does it have a leading 9 or 1, if needed? If that all seems okay, try connecting an telephone handset to the modem phone line. Is there a dial tone? Can you dial out to the paging vendor? Does the vendor's modem answer? If all that seems normal, you may need to contact your phone company.
The paging vendor's modem is not answering.
Call your paging vendor and verify the number Robot/ALERT should dial. Don't forget to adjust the dialing sequence if a leading 9 or 1 is needed.
The number that the modem is dialing is answered by a voice rather than a modem tone.
Call your paging vendor and ask for the TAP modem phone number. Change the number Robot/ALERT is dialing to this number.