Just as you had to complete all the required tasks in Wizard City before you were invited to move on to Krokotopia, so must you complete all the required tasks in Krokotopia before you will be given the Spiral key to Marleybone.
Complete the Krokotopia quests you have in your quest journal and more will open up to you, setting you back on the path to continue the required story-line quests. Don't be in such a hurry, young Wizard. The fun is in the journey, not in reaching the destination.
I have a mission to go to Marleyborne but for some reason on the Spiral I can't access it. Does anyone know how to fix it?
You have to complete Krok in order to get the Spiral Key to enter MB. More examples on how to enter MB without finishing up Krok is 1- Port to friends in MB, 2- Buy MB with crowns if you don't have membership or 3- Finish up Krok WITH friends. Hope this helped!