For doing business with a company I have to browse to https://www.prioenergie.de/nc/mein-prioenergie.html (German website).
Firefox says the certificate is invalid, because it is not signed by a trusted root CA.
This is the certificate data:
Created for CN: www.prioenergie.de Serial: 1A:AE:76:6C:D0:09:24:AC:41:07:2D:27:7E:42:4A:FB Created by CN: thawte DV SSL CA - G2 O: thawte, Inc. OU: Domain Validated SSL Valid from: 06.11.2014 01:00:00 valid through: 12.09.2017 01:59:59 SHA256 fingerprint: 45:8B:50:A6:21:F1:17:7F:AE:63:24:EE:ED:DA:CE:6A:53:38:C4:AC:F6:48:0D:0A:52:49:F8:B3:07:4E:1B:25
What I did so far:
- I already googled for the fingerprint, but didn't find anything useful.
- I wrote an email to the support hotline and told them to investigate in this issue
- I have submitted the URL at SSLLabs and it got a grade C, which is certainly not the best, but also not very meaningful for me.
What would be the next step to find out whether I can or cannot trust the certificate?