Try these steps first to narrow down the source of the issue:
If you are using a cordless phone, disconnect all cordless phones from phone jacks. If you have a corded phone, try it in the same jack. If you are able to receive calls, there may be a problem with the phone.
If you cannot check the connection with a corded phone, unplug the cordless phone from the power supply for at least 15 seconds and try again.
Try plugging your phone into another jack. If an alternate jack works, the first jack may require repairs.
For further assistance or repairs, call SkyLine/SkyBest Repair Services at 1-877-475-9546.