Hello,
A bit of background: When authorising a publishing channel, the Alfresco repository needs to be able to construct a working URL to the Share instance. In the case of a Twitter channel, this then gets sent to them as part of the oAuth communication. The domain (protocol, host and port) you use to view Share needs to match the domain that the Repo thinks Share is on & this is checked client side before the oAuth request proceeds - I needed to add this check to prevent even more confusing error messages caused by tripping over the browser security model if the domains didn't match.
The fix: The settings you need to check are share.host and share.port and share.protocol in alfresco-global.properties. The default host is {localname} which corresponds to the what the server thinks is it's hostname. This might be where you are getting Alf or 127.0.0.1 from. The settings for those values should match exactly what you type into the address bar.
Will: the connection is made by the user's browser so in this case, the internal hostname and port should work fine.
Hope that helps,
David.