CouchPotato images not loading?

[ujellyx]

When i choose the CouchPotato menu none of the images (thumbnails, etc.) are loading properly. When i try to enter the image-url manually (e.g. http://localhost:8085/couchpotato/GetImage?w=154&h=231&url=https://image.tmdb.org/t/p/w154/fYzpM9GmpBlIC893fNjoWCwE24H.jpg) i always get the following error:

500 Internal Server Error - The server encountered an unexpected condition which prevented it from fulfilling the request.

Though the image-url itself (from tmdb) is okay.

Here a picture of how it looks:

Log says:

2016-03-13 01:08:45 cherrypy.error.28113936 ERROR [13/Mar/2016:01:08:45] HTTP