The request failed with the error message: -- <html></html> --

Hi guys!
One of my pc clients has dropped and cannot connect to the CMS anymore :frowning:
It keeps showing the following error when i try to connect it,
“The request failed with the error message: – --.”
Both cms and player are 1.8.11
I have reinstalled the player but it didn’t help, same error.

Any ideas what is this about?