Symptom
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
Resolution
Note: 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.
- 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.
- Next, check if the device is on the recommended firmware.
- Check the firmware of the phone by pressing OK.
- Confirm the version needed. See Check Firmware Version on Yealink T4x Series.
- 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.
- 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 see What is the recommended firmware for 8x8 phones and analog adapters?
- 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.
- Make sure to provision the phone to 8x8 server.
- Go to Settings > Auto Provision.
- Enter Server URL: https://ylcfg.8x8.com/yealink/
- 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
Cause
- Phone has an incompatible firmware.
- Phone is unable to successfully register a SIP account with our services.