Password required to start nengo

[Kougakujin]

Issue description: For some unfathomable reason I tried starting nengo at some point and I reached a page with the following: "Please enter the password or the security token shown by Nengo when it was started:". Now when I provide the token from the command line I get: "Invalid password. Try again."...

Reading through previous issue entries linked the keyword 'password' it seems there is a link to which browser is being selected upon startup. However, what makes this most mystifying is that I have not changed browser or had any issues running nengo on my Firefox before. I simply tried running nengo at some point and instead of the usual interface I got the error message...

I since tried upgrading nengo as well (and I did to version something.8), but no luck. Any advice would be most appreciated.

[jgosmann]

Try clearing your cookies.

If that doesn't help: Did you try to copy and paste the full URL into the address bar of your browser?

What are the exact version of your browser and Nengo GUI?

[Kougakujin]

I tried a few things and then figured it out... If I have 'hanging clients' (clients that I opened and then I closed the nengo window without terminating the command line process) I get this problem. The solution is to make sure all open nengo windows AND terminals are closed before opening a new one!

[jgosmann]

The command line process should terminate itself once you close the browser window.

If you are opening multiple GUI instances at the same time, it might be the same problem as reported in #978 which should be fixed with the PR #981.

[fangwei123456]

When jupyter notebook is running some nengo code, this error will happen. Just shutdown the jupyter notebook..