Wow! I thought I was the only one. Couldn't find any information anywhere so I thought it was an error on my end.
I have the exact same issue. Jdownloader can't connect to anything. My premiumizer container can't connect to it. It can't check its accounts and it can't connect to the myjdownloader service.
I already removed the whole container and reinstalled it but no success so far...
Anybody who could help us?