Unable to reach 3CX License Activation Server. Confirm that your Primary DNS Server is able to resolve activate.3cx.com

[ccasalicchio]

Greeting!

I have followed the steps from https://www.3cx.com/community/threa...x-18-0-update-3-build-461.120928/#post-564879
The current version is 18.0 Update 7 (Build 424)
And just reinstalled my system, yet I'm still getting this error:
Unable to reach 3CX License Activation Server. Confirm that your Primary DNS Server is able to resolve activate.3cx.com

I tried ping and it's reaching the site:
root@3cx:~# ping activate.3cx.com
PING activate.3cx.com (104.18.15.54) 56(84) bytes of data.
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=1 ttl=60 time=10.2 ms
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=2 ttl=60 time=8.70 ms
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=3 ttl=60 time=9.48 ms
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=4 ttl=60 time=13.6 ms
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=5 ttl=60 time=9.23 ms
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=6 ttl=60 time=9.53 ms
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=7 ttl=60 time=9.12 ms
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=8 ttl=60 time=11.0 ms
64 bytes from 104.18.15.54 (104.18.15.54): icmp_seq=9 ttl=60 time=16.7 ms

And now the license page is not showing anything.
I did setup my secondary DNS to 1.1.1.1 and port forwarding has been configured
What could be wrong? (I have been using 3CX for over 3 years now)

 

[SteveITS]

Is HTTPS and/or all outbound traffic allowed from the 3CX server out to the Internet? Any IDS/security that might be blocking it? Port forwarding is for inbound connections.

 

[JohnS_3CX]

The ping test only demonstrates that you are able to ICMP ping.

It does not mean that the server can establish a TLS session with 3CX activation.

This type of issue can occur if your firewall is blocking / modifying the traffic due to its policies

 

[ccasalicchio]

We added the activate url to the router, and it's now working, thanks!

 

[AliYikilmaz]

I have same problem with fresh installation. i check all another post still no luck here.
i can reach fqdn
My primary server is 8.8.8.
Firewall totally disabled.

# nslookup activate.3cx.com
Server: 8.8.8.8
Address: 8.8.8.8#53

Non-authoritative answer:
Name: activate.3cx.com
Address: 104.18.14.54
Name: activate.3cx.com
Address: 104.18.15.54
Name: activate.3cx.com
Address: 2606:4700::6812:f36
Name: activate.3cx.com
Address: 2606:4700::6812:e36