Check the code of your registration form and the registration action.

I've checked everything and can't see where a problem would be coming in. The registration form action is set to /action/register, so that's correct. Not sure what's supposed to happen after that.

did you manage to figure it out? My sites register form is doing something similar and Im pulling my  hair out!

If someone goes to register page, fills in details and clicks finish... it simply reloads the register page (with blank fields)

any help would be much appreciated!