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8x8 Support

Yealink T4x Series IP Phone Displays No Service


8x8 is not responsible for any issues or problems it may cause for devices purchased elsewhere.

These are tested for use on 8x8 purchased Yealink devices.


Yealink T4xG series (T41P/G,T42G, T46G,T48G) and Yealink T4xS series (T48S,T42S,T41S) phone LCD display shows the message "No Service". There is no dial tone, and you are unable to make or receive calls. 

Applies To

  • Yealink SIP-T41P/G 
  • Yealink SIP-T42G 
  • Yealink SIP-T46G 
  • Yealink SIP-T48G
  • Yealink SIP-T41S
  • Yealink SIP-T42S
  • Yealink SIP-T46S
  • Yealink SIP-T48S


  1. In cases where the phone had been properly working for a long time and is only suddenly afflicted with these error messages, power cycling your network is often able to clear it up.
  2. Next, check if the device is on the recommended firmware.
    • Check the firmware of the phone by pressing OK.
    • Confirm the version needed here.
    • Another way to check the version is via the web GUI by obtaining the IP address from the phone or the Client list table from your router.
      • Log in to the phone's IP address (default user/password: admin/admin).
      • Navigate to Status > Status > Firmware Version.
  3. If the device is not on the same firmware, either newer or older; flash it to the recommended version.
    • Request to for the correct firmware file, you can confirm the version needed here.
    • Next, go to Settings > Upgrade > Select and Upgrade Firmware.
    • Click Choose File choose the firmware file saved previously, and press Upgrade.
    • The phone will reboot and update it's firmware, once done proceed to the next step.
  4. Make sure to provision the phone to 8x8 server.
    • Go to Settings > Auto Provision.
    • Enter Server URL:
    • Click Autoprovision Now.
    • The phone will reboot twice and once booted, will have the chance to activate.

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
  • Try setting a static IP on the phone, which has been known to help resolve these issues. 


  • Phone has an incompatible firmware.
  • Phone is unable to successfully register a SIP account with our services.