I have successfully uploaded a world however i can't access it. I have found that it is not under the worlds tab in file manager. I'm not sure if that is the problem, but either way i don't know how to fix it.
it is happening to me as well
I'm on a mac would that be a problem?
edit: i found a solution. drag your server dashboard into its own window. then put drag it into its own desktop. this should allow you to click on the top half of the button. I hope this will help you.