If I retry right after it happens to the same server I get in. Other times I'll get in without this error ever appearing. After 2 days of trying to reliably replicate it I'm posting it and maybe you have an idea what is going on and why.
The only interesting thing in the factorio log is
log excerpt
I see that 0.14.17 is out now. I'll try that tomorrow and see if this error message is gone or still randomly reappears.