Fetching the page failed (..) only on HTTPS



I got the standard: Fetching the page failed due to an internal error, debugId: 1409527398-563497

But only when i activate SSL (https://). On the normal http:// URL it works just fine.
I also noticed when i try on http:// that the image not gets loaded, because it has https:// in front of it. (again, if i change it to http://, there is no problem)

My certificate is from Comodo Essential SSL