Can't create new xmpp account from Jitsi

Hello everyone,

I have openfire installed version 3.9.3 with embedded database.

I create user directly in openfire, it works but I want to create a new xmpp account from Jitsi (view attached file) and I have this error:

Unknown XMPP error (XMPPError connecting to myxmppdomain:5222.). Verify that the server name is correct.

note: It only works if I use the name of openfire machine, but when I use openfire domain in server it doesn't work. (Users cannot know the name of the machine if they want to create account so it is  a problem, they know just the domain (mydomain.com) ) .

One more question: If we can create accounts locally, Is there any way to create automated accounts?

Thanks for help