Problem

Your Yealink SIP-T23P or SIP-T23G phone LCD display shows the message No Service. There is no dial tone, and you are unable to make or receive calls.

Cause

Your phone is unable to successfully register a SIP account with our services.

Resolution

In cases where the phone had been properly working for a long time and is only suddenly afflicted with these error messages, a network power cycle is often able to clear it up.

Other helpful network troubleshooting:

  • Swap out the Ethernet cord connecting the phone to the network for a different one (to see if a faulty cord might be the issue).
  • Is the phone connected to a wall jack? If so, try connecting it directly to a networking device (router or switch).
  • If the phone is connected to a networking device, try plugging it into a different port on the device (to see if a faulty port is the issue).
  • If accessible, review the firewall/router settings and be sure to disable the following:
    • SIP-ALG
    • SPI
    • Firewall

You can also try setting a static IP on the phone, which has been known to help resolve these issues.


No resolution?

Contact 8x8 Technical Support