I'm experiencing the same difficulties. I can log on to the website or the app, but as soon as I go to my account page it either shows a blank page or an error. Happens to me on my mobile phone, Firefox, Chrome and Explorer. I want to cancel my premium account, but this way it is impossible.
Same here. The account page refused loading when I tried joining a family group from a Premium trial account. Since then (it was yesterday), I cannot go to the account page. I tried on Chrome, Firefox and from the Desktop app.