Warning about expiring Certs since Update to 9.5

Dear,

after updating to 9.5 last night I found an E-Mail this Morning with a Warning about expiring Certs:

2 certificate(s) will expire within the next 30 days:
D78A7D5D5D37A4C4, 8825274F5DFEE296
--
System Uptime      : 0 days 4 hours 11 minutes
System Load        : 0.26
System Version     : Sophos UTM 9.501-5

Please refer to the manual for detailed instructions.

In deed I have one Cert (Proxy CA) that is expiring on July, 21, 2017.
But I can not find the 2nd one.
And none of the Thumbprints (or what are "D78A..." and "88252..."?) belongs to my Proxy-CA-Cert.

Somebody an idea?

Thanks in Forward!

TJ