Can't access account settings after upgrading to premium family

[L101]

I upgraded to Premuim for family 30/12/17 and am in Australia.  Since doing so, I have not been able to access my account settings to invite family members.  I receive an error screen showing 500 error 'We're all mixed up'.  Is anyone else having this problem and how do i fix it?  Interstingly I could access the screens to pay to upgrade, but my family can't actually use the upgraded feature...

[Luke]

Hey @L101,

have you tried to use an incognito tab, clear the cookies of your browser and use another browser or device?

When this doesn't work, you should try to use another internet connection (e.g. cellular data instead of WiFi).

Have a happy new year!

LK608