So following up with this Report that is falsely marked as solved:  clearing cookies does help but only temporarily. I did not yet find out what exactly is the condition but think I did find out which cookies are the reason for it (so deleting only these cookies already helps for a moment): rxd-init and txd-init   Here is the error message when vnc doesn't work: May 21 20:15:15 Storinator nginx: 2022/05/21 20:15:15 [error] 29980#29980: *351315 recv() failed (104: Connection re