Yes, first I restarted the client quite a few times. Then I realised I didn't have the newest loader, so I downloaded it and gave that a try. After this message was displayed, I restarted the client several times and kept trying. About 5 minutes later, I restarted my computer and tried again which didn't work, so I restarted my computer once again.
As you are probably aware of, I'm not the only player experiencing this error.