Error with "Forbidden" on runtime reconnect [git master]

[jonnor]

Open a project with a runtime associated. Hit runtime reconnect (refresh icon). After half a second an error "Forbidden" appears. The runtime area now shows "Select runtime"

After this most actions seem to trigger the Forbidden error again. Example: Typing in component search bar.

Tested with Microflo 0.6.5 in Firefox 59

[jonnor]

In the console there is

pong: null LoggingMiddleware.coffee:56:18

though this only seems to happen when pressing reconnect, not the other actions that then trigger the error