Solved T54W SBC/router phone

[sergen]

We have a curly situation.
We won a job so we configured everything in our office with T54W SBC/router phone and connected the T43U phones. Everything worked fine without a hitch.
but when we took it onsite to cutomer premises all the T54W phones come up with red exclamation mark when you click on it the message says provisiong credential errors.
Defaulted the phone/phones again and came up with same issue.
took it back to our office and it all worked.

checked their network for sip ALG and there are no sip ALG.
Ask the business MSP to ensure firewall is not blocking it. He said he put all the phones into a DMZ zone and everything was allowed but still having same issue.

its a 3cx hosted 16SC pro license.

does anyone have any suggestions?

 

[Craig Catlow]

Just out of interest, where are the phones in the DMZ getting their IP addresses from?

 

[sergen]

from the dhcp server - fortinet firewall/router

 

[Craig Catlow]

I would take a couple of the phones out of the DMZ along with one router phone and see what happens.

 

[sergen]

even outside the DMZ we have the same issue.

 

[JohnS_3CX]

Defaulted the phone/phones again and came up with same issue.
took it back to our office and it all worked.

This tells you everything you need to know. If you don't control the customer's networking, it will be entirely up to them to troubleshoot this at the network level.

I'm not sure there is much more you can do from your end.

 

[Craig Catlow]

I agree @JohnS_3CX. Looks like a Fortinet issue to me.

 

[sergen]

it's 100% firewall issue but the IT person won't budge. So added a second NBN with my own router and switch and everything worked as it supposed to do. I said to the customer I have proof to you that the 3cx is not at fault. The ball is in their IT person hands.
The agony is customer still thinks 3CX is a lemon but in fact their IT person is a lemon.

 

[DrLloyd]

hook a laptop up on the vlan the phones are on- can you get internet access? The policy in the fortinet still needs to allow the traffic out.

 

[sergen]

The issue was firewall and this is now resolved.

 

[DrLloyd]

thank you for being one of the few people that acknowlege when something is resolved.