SD-RED connection problems

Good day,

we have seriously connection problems with a SD-RED60. It works fine till the connection gets interrupted about once an hour for mostly 3-4 minutes. After the interruption, the connection works again fine. Both WAN IP Addresses are available during the issue and PING(WAN) works fine, we don't have any Internet failure. 

Is there any option to check all the Logs from the SD-RED Box?

At the moment it looks like that the tunnel is fine, which says the Sophos XGS. LAN Port1 to Switch and LAN2 Port direct to PC (test) aren't available during connection issue.

Hope someone has an idea

Thanks!

Sophos XGS 19.5.0 GA

SD-RED60 3.0.008 WAN is configured as Failover