Server running except.

Hi, I got my server and site running smooth but.. i have few problems heres the list:

Logging in problem
1.They can see my site and every thing they created account peferct no problems but... now they say they can't log on my game they say it says disconnected why? what should i set my ip settings for my mangos and realmd at? also for my host thing were it says 127.0.0.1 Localhost should i do any thing there?

Mount problem
2. My mounts arn't working only one that doe's work is my Tiger mount's thats in darnassus. How do I get the horse riding skill to work i can see the guy who sells horses but were is the instruckter who teaches u how to ride horse?