Ngrok errors '502 bad gateway'

Quite new to using any sort of Web App stuff, and I've been trying to slowly build a Facebook Messenger Bot. When I try to use ngrok I can't visit the address I'm given, i.e:

ngrok http 5000

is what I'm putting in the command line, and it's returning this:

ngrok by @inconshreveableSession Status                onlineVersion                       2.1.18Region                        United States (us)Web Interface                 http://127.0.0.1:4040Forwarding                    http://ea986ca5.ngrok.io -> localhost:5000Forwarding                    https://ea986ca5.ngrok.io -> localhost:5000Connections                   ttl     opn     rt1     rt5     p50     p90                              0       0       0.00    0.00    0.00    0.00

But when I take the address 'https://ea986ca5.ngrok.io' as is required by the Facebook developer's page, it says:

The connection to http://ea986ca5.ngrok.io was successfully tunneled to yourngrok client, but the client failed to establish a connection to the local  address localhost:5000.Make sure that a web service is running on localhost:5000 and that it is a valid address.The error encountered was: dial tcp [::1]:5000: connectex: No connection could be made because the target machine actively refused it.

Is it a problem with my local port?

I can't access localhost:5000. I don't have a server listening on it.