I tried this

mfoss — Mon, 26 Aug 2013 11:19:13 +0000

I tried this configuration:
{hosts, ["localHOst"]}.
with ejabberd 2.1.13 and JWChat. It can login correctly.

Anyway, I don't understand why would anybody want to use capital letters for a virtual host name in ejabberd.cfg

In XMPP, the server part of the JID is case insensitive: localhost and loCALhost are equivalent.

ejabberd - Comments for "a bug in Virtual Host names with mod_http_bind and CAPITAL letters"