You will probably not be able to connect to that server using SSL. Try unticking that option. If you still can't connect, check the username. Does it matter that you have a leading cap in it? IDK.
How my installation works:
I installed the chat client "Pidgin" on my PC (because it is thin.) In it, I had to configure my own personal Jabber account information, so I needed to create a personal Jabber account as well as an account for my forum.
Other forum users are not required to install a chat client to send messages to users who have a Jabber account linked in the forum, and who have the client installed. But, if they want to receive IMs from other forum users, they will have to create an account of their own at Jabber.org, and install a chat client on their PC that supports the XMPP protocol (and thus, one that supports Jabber.)
Not every chat client supports XMPP. Skype, for example, does not yet, and from what I've read google chat requires all chat partners to be google buddies, although I really don't know about that yet. XMPP enabled chat clients are listed with download links at http://xmpp.org/xmpp-software/clients/
Once the chat client is installed and configured properly, users must edit the Jabber field in their User Control Panel to include their own Jabber login (not that of the board.) Mine is email@example.com
, and as you can see, my board's Jabber account is firstname.lastname@example.org
. After they do that, a small round Jabber icon will appear under their profile photo in posts, and anyone can send an IM to a person with that icon. Again, if they want to receive a message in return, however, they will need to install the client and add their Jabber information to their own UCP.
Here is my working phpBB3 setup.
Enable Jabber: Enabled
Jabber Server: jabber.org
Jabber Port: 5222
Jabber Username or JID: email@example.com
Jabber Password: my forum's account password
Use SSL to connect: tick No
Jabber package Size: 0 (generates a popup notice to a given user on every message sent to them - increase this number to package them in multiples before sending.)