portal premium ???

I had the same issue for the past hour now. Left the page open while searching for any possible solutions online for about 20 minutes and with a completely unmodified experience I hit save at the top right and it saved and I used that opportunity to modify the experience from there. Not sure what the problem is exactly but I have a feeling it's tied in with the overpopulation problems they've been having in general. Might try just sitting and waiting and hoping it finally just saves or if enough people email support with open cases about the issue it will definitely catch their attention to get it corrected sooner.