You have to finish, ALL the quests in the Throne Room of Fire, Royal Hall, etc.
When you do someone will tell you to talk to Sir Major Talbot, he'll let you.
If it still doesn't work, you'll just have to ask a friend to go there and you teleport to them and mark that location. Try riding the boat back. If it's successful, you'll probably be able to ride there.
You get the quest to go into the krokosphinx but that isn't permission. you have to defeat the throne room of fire. by defeating 4 nirini bosses in a row. Like Akori. Then you defeat the throne room of fire and get npermission. you can have someone take you there and you can mark the location. Stephanie Fireflame lvl 24 Adept Pyromancer
every time i try to talk to niles ( the tree at krokospinx ) i have to get on a boat and it will not let me get on the boat so i ask the captain and he said i had to get permision from sergeant major talbot and i go to ask him and he says,"im woored about some one can u give me a hand and go look for him please ".