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Full Version: Yealinks T2xP do not respond to INVITE requests
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We are using 3cx IP PBX and Yealink T26P and T28P IP phones.
Lately we have noticed the following issue from time to time:

During incoming calls, 6 (six) Yealinks which are members of a Ring Group receive the INVITE requests from the 3cx server, but they do not respond, neither with a provisional response (1xx) nor with a final. As a result, the server retransmits the INVITEs towards the Yealinks and the Yealinks never ring.

We have captured Wireshark traces on the 3cx server and we can see indeed that the INVITE requests leave the server and head towards the Yealinks.
The server and the Yealinks are within the same LAN, and the Yealinks were all registered by the time of the incoming call.

They are running and respectively.
Is this a known issue in the above versions?

Please let me know if you need additional information.
Never ran into that myself but we peaked out T28/26s at as that was the last super stable version and we never bothered to upgrade to V73 firmware.

We run with Asterisk not 3CX so can't confirm, but maybe try rolling back to and see if that resolves the issue, then you know for sure its a bug. Keep in mind T28/26 are EOL long ago now so chances of any fixes are probably non-existent, so finding an existing firmware that works is your best bet.
Thank you for your reply jolouis.

Unfortunately the versions we are using are the latest supported by 3cx.
So, we are a bit concerned to deploy newer versions for our Yealinks, as we are not sure if this might cause interoperability issues with 3cx.

This is why I was wondering if there is any known issue in the specified versions, and
So, anyone who could confirm any known bugs on or

Also, where could I find version just for testing?
The following link does not include it:

UPDATE: I downloaded the suggested from this link:
The result is that my test Yealink is now totally broken. Cannot access it via HTTP, even if it actually gets an IP address. Please suggest where I can download the version above and if you have tested successfully rolling back from Thank you.

Thank you,
That pretty odd that the phone broke completely. Unless you updated the wrong firmware (i.e. tried to install T26 firmware onto a T28 or vice versa). Typically after a firmware change you need to do a full factory reset of the phone (press and hold OK button for 10 seconds then hit "Yes" to confirm). Once that completes the phone should boot up and work normally (and re-provision if you have provisioning in place).

There are enough firmware files on that site to look like they are not spoofed or hard coded for anything, but if you need the generic firmware just let me know I've got copies here.
Hi jolouis.
Yes, please, I would like the and the (T26P) firmware.
Can you share copies?
(01-29-2019 07:33 AM)gtsionos Wrote: [ -> ]Hi jolouis.
Yes, please, I would like the and the (T26P) firmware.
Can you share copies?

Here you go:
Reference URL's