IPsec tunnel go down after some hours

Hi, we have a Sophos XG210, SFOS 19. We set a site-to-site VPN tunnel to SAP with the parameters they gave us. 

Locally, we have the network 10.X.X.X and 192.168.X.X (we are migrating to all class A), and SAP & 

The tunnel works OK. We have connection between local hosts and remote servers in the SAP cloud. But, after some hours the tunnel goes down (I don´t know if it is important, but we are implementing SAP, there is only test traffic, not working officialy with SAP). 

The status apears ACTIVE (green) but CONNECTION in YELLOW. If I restart the connection, the tunnel goes up and works OK.

 If click in the information appears near "connection" item, I see that: 

The problem is only with network class A. In the log console appers this message: 

I don´t know if the problem is in SAP side, or maybe I need to configure a more specific network in my site (no /8)

Edited TAGs
[edited by: emmosophos at 10:51 PM (GMT -7) on 25 Aug 2022]