Recently, quite out of the blue I started seeing this error when I tried to log into my SQL instance using SQL SERVER Management Studio (SSMS)
Now, I could RDP to the server and connect to the local instance using SSMS, however any attempt to connect to the server from a remote client failed with the above error.
Now, the server was a VM, which had migrated to a new host fairly recently and as it turns out had picked up an incorrect time from that host.
After resetting the time and updating the time syncronization the error dissappeared.
As this was a non-production server, I had the luxuury of being able to re-start the sql instance and even machine pretty easily, but in case you see this issue in production it can be fixed with a reboot of any kind simply by making sure the time is correct.