ERR_CONNECTION_REFUSED

[Gtaucher]

Hello,
I'm having this problem.

Failed to load resource: net::ERR_CONNECTION_REFUSED
polling-xhr.js:263 GET http://localhost:8080/socket.io/?EIO=3&transport=polling&t=MD5IkiX 0 ()
i.create @ polling-xhr.js:263
i @ polling-xhr.js:165
o.request @ polling-xhr.js:92
o.doPoll @ polling-xhr.js:122
r.poll @ polling.js:118
r.doOpen @ polling.js:63
r.open @ transport.js:80
r.open @ socket.js:245
r @ socket.js:119
r @ socket.js:28
r.open.r.connect @ manager.js:226
(anonymous) @ manager.js:540
setTimeout (async)
r.reconnect @ manager.js:530
r.maybeReconnectOnOpen @ manager.js:208
(anonymous) @ manager.js:250
r.emit @ index.js:133
r.onError @ socket.js:685
(anonymous) @ socket.js:276
r.emit @ index.js:133
r.onError @ transport.js:67
(anonymous) @ polling-xhr.js:128
r.emit @ index.js:133
i.onError @ polling-xhr.js:309
(anonymous) @ polling-xhr.js:256
setTimeout (async)
hasXDR.n.onreadystatechange @ polling-xhr.js:255
polling-xhr.js:263 GET http://localhost:8080/socket.io/?EIO=3&transport=polling&t=MD5Ilt1 0 ()

Where can I check to find the solution?
My installation runs on Ubuntu 16.04.
Thank you

[Dan Fisher]

Can you clone or download the most recent release and see if you are getting the same error. Also, what web browser are you using to view the web app?