If your captive portal doesn't pop up the most common issue is that Spotipo servers are not allowed through firewall.

To check this, go to firewall settings on your UniFi controller and check if there is a firewall rule called spotipo_allow (it could be called differently if you have used a different name). This rule should accept connections coming from our servers. Configuration is pictured below.

Also, make sure that the address (in this example spotipo_servers) group contains these addresses.

You can check this under Profiles -> IP Groups

If everything was okay with your Firewall settings, second common issue could be domain option not being turned on in your hotspot settings.

To check for that, on your UniFi controller, go to Insights ->Hotspot -> Landing Page

Go to settings of Hotspot and check that the domain option is turned on and that the domain is set to app.spotipo.com. Also make sure that the addresses 107.178.247.148 and app.spotipo.com are allowed in the Authorization Access tab.

If this still doesn't fix your issue, there is a known bug, which stops portal from opening if there are too many Pre-Authorized addresses in the Authorization access tab. Remove some of the unnecessary addresses to try and fix the issue.

If your problems are still not fixed, check the status of your controller in Spotipo portal.

To check your controller's status, go to Settings -> UniFi Controller. If everything is set up correctly. Controller's status should be Online.

If status of the controller is either Not Reachable, or Invalid Credits, the problem is in communication between UniFi controller and our server.

If you are using DDNS, the problem might be that your address is not updating automatically. Check the solution to this problem here.

If you are using reverse tunnel, it could be possible that the reverse tunnel is disabled/not running. Check the solution to that here.