Vpn ipsec site to site between sophos xgs and RUT271 with a SIM card

Hi.
In my environment I need to connect two sites:

  1. Head Office with a local connectivity and static IP address behind a Sophos XGS firewall;
  2. Branch Office with a SIM card connectivity with a Teltonika RUT271 (with latest firmware 7.13.4).

I configured a tunnel in both sides with this parameters below and a PSK:

Phase 1: AES 256, SHA512, MODP4096, 24H;
Phase 2: same as Phase 1.

Teltonika start the tunnel calling IP address behind Sophos; Sophos is waiting for a calling and answer when Teltonika start Phase 1. I see that tunnel seems to be up, I can see this on Sophos dashboard and in Teltonika VPN status. But I cannot ping anything in both sides.
I see that I’ve TX traffic but no RX.

I think that is not a Sophos problem because I know the product and I configured it many times with other brands and I always connect two sites with VPN. I think it can be a misconfiguration or something like this in Teltonika that are newly for me.

What can I check?

Many thanks in advance.