"Can't connect to login server" Error in Browser

Hello, am getting this Error message yet Perceptilabs starts fine in the terminal but not working in the browser.
How can this be solved?

Hi @alz,
Welcome to the forum!

How does it look like in your browser console (F12)?
And does it work if you try with another browser?

All the best,

@robertl I tried other browsers but still the same issue

Hi @alz

This just happened to me, and though you might be experiencing a different problem maybe this will help someone

When I was unable to connect to the login server it turned out that I had accidentally started two (or more) instances of PerceptiLabs; another one might also have been logged in, but the server was definitely up.

Now, PerceptiLabs currently lives on a fixed port (8080) and if that port is already in use by something else it might cause the login problem. When I closed all my PL instances and started from scratch I was able to log in again.

Lots of speculation here, but IIRC it is quite easy to check which ports are already open… if 8080 is already occupied you can quit whatever is using it and see if that resolves the issue.

Let us know how it goes!

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My fixed port 8080 is free & still it’s no working

Thanks for the screenshot @alz,
Would you mind navigating to the Console tab as well so I can see if there are any errors? :slight_smile:

This is an issue we have seen happen for others who have been under a (for example enterprise) firewall, where it blocks the connection to the login server. Port 8443 needs to be open for it to work.


@robertl i use Kaspersky Total Security. Does it interfere with this issue? Regarding network ports

It looks like it may, you might need to manually unblock port 8443 if it’s blocked.

@robertl I don’t know if there’s another solution but it has failed too :slightly_frowning_face:

@jon or @rohan.m, do you know anything else we can try?

Hi Alz,
Our tool uses few ports to run all the services, can you please check if your port 8011, is available?
Let us know if that works. For your reference please keep port- 5000, 8000, 8080 and 8011 free for perceptilabs.


am using CurrPorts to check for the ports but it seems like the ports are free. They are not being used by anything @rohan.m

Thanks for providing me the list. Can you cURL to localhost:8011 and tell me what it is response you are getting. Also, if possible can you drop message me on Perceptilabs community slack. It will be faster to debug there.