stun remote yealink phone not connecting

[Song]

Hi,

We have 3 phone in this remote location, which we call office1. one of the phone went RED on the portal and it is not connecting for some reason. We swapped the phone with one in a differnet room and it worked. So it is not a cable issues. We then took the phone that didn't work and plug it to a place where the phone was working. Still the phone is not registering.
I checked the activities log and i do not see any connectiong to it. Anyone why? i set it to debug mode and nothing is coming into the logs.
Anyway, i reset the router and also restarted the 3cx services all. and now the other two phone is not registering.

So i add in a dummy test account into 3cx and reset my yealink phone and copy and paste the stun URL into the provision phone and it worked at my HOME office. So the 3cx server is working fine. For some reason it is only that location. I can't seem to debug this. Anyone know what to look for?
I thought it was a DNS issues, but i manually set it to 8.8.8.8 . Still no go.

I have delete the extension and re created it and reset the yealink phone and apply the stun URL and still no luck. need some guidanace into this issues.
I checked the firewall and no changes was made. I tried to change the port on the SIP on the phone to a differnet port and still no good. i use 5065, first phone, 5066 second phone and 5067 3rd phone.

Maybe the internet carrier is blocking some port? please advise.

thank you

 

[complex1]

https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

Check if IP address of Office1 is not blacklisted.
Check if SIP ALG in Office1 router is Disabled.
In the Office1 router, each phone must have his "own" dedicated and fixed IP address and ports, and these ports must forwarded to the phones.
e.g.
Phone 1, local SIP port 5062, local RTP port 14000-14019
Phone 2, local SIP port 5064, local RTP port 14020-14039
Phone 3, local SIP port 5066, local RTP port 14040-14059
and last but not least... reset the phones to factory default before you try again.

 

[JohnS_3CX]

As above, but make sure you have factory reset it, make sure you are not using custom templates.

 

[Song]

https://www.3cx.com/community/threads/information-to-provide-when-requesting-help.67558/

Check if IP address of Office1 is not blacklisted.
Check if SIP ALG in Office1 router is Disabled.
In the Office1 router, each phone must have his "own" dedicated and fixed IP address and ports, and these ports must forwarded to the phones.
e.g.
Phone 1, local SIP port 5062, local RTP port 14000-14019
Phone 2, local SIP port 5064, local RTP port 14020-14039
Phone 3, local SIP port 5066, local RTP port 14040-14059
and last but not least... reset the phones to factory default before you try again.

My finding.
1. Its either 3cx hosted server is blocking something from tha IP on a firewall level. Again I i spin up a new phone to connect to it it work fine from a differnet location.
2. The Office1 internet service provider is blocking something. Which it didn't happen before.

I have checkd the blacklist and nothing is blacklisted
SIP ALG in office1 is disabled
Office1 each phone does have its own IP and port forwarded to the correct one. No changes was made.
Reset the phone to factory default. Login to the phone and copy and paste the STUN URL and hit Ok and provision now. It still doesn't connect.


Thank you for the sugestion. I have spend 4 hours troubleshooting this with no luck so i decided to spin up a VM locally and migrate the 3cx hosted to it and everything worked.