IPsec connection could not be established

Hi Fotit As an already working connection is breaking for you it might require some advanced troubleshooting from CLI logs and packets. You may validate the strongswan debug logs on both the XG CLI and may validate packets on Remote GW IP on both the end XG vice versa.

Sophos Firewall: Troubleshooting site to site IPsec VPN issues

Regarding the tunnel is up but no traffic please check below KBA and RR to validate more:

Sophos Firewall: Troubleshooting steps when traffic is not passing through the VPN tunnel:

https://support.sophos.com/support/s/article/KB-000035835?language=en_US#

How to Identify the communication issue with up and running IPSec tunnel:

How to Identify the communication issue with up and running IPSec tunnel 

Hi Vishal,

Okay, but before to do this, Maybe the difference in versions can cause this malfunction ??

HQ: XG330 (SFOS 18.5.4 MR-4-Build418

BO: XG86w (SFOS 19.0.1 MR-1-Build365) 

Thanks

Hi Fotit  Very less chance that version differences cause such a malfunction. 

Thank you Vishal for your feedback

So i try to follow the instructions in the links given

I checked the priority of VPN and static routes

I find this order:

1-SD-WAN Policy routes

2-VPN Routes

3-Static Routes

I think it's normal, because they are not SD-WAN routes and no SD-WAN Profiles?

Hello Vishal Ranpariya

The problem was on Telecom Provider network, may be routing problem.

So now the ipsec VPN is active and connected.

Thank you for help.

Hello Vishal Ranpariya

The problem was on Telecom Provider network, may be routing problem.

So now the ipsec VPN is active and connected.

Thank you for help.

Hi Fotit  Thanks for sharing the resolution details for wider audience reference.