Can't create anything in a new portal - creating the resource group 'X' would exceed the quota of '300'

I can't create anything in a new portal anymore. I'd like to create Redis Cache and DocumentDB resources, so I can't do that in old portal.

While adding new Redis Cache or Document DB I'm getting an error:

Maybe it's related, but opening "Resource groups", "Web sites" or "Virtual machines" shows infinite "Loading..." message.

Please help. Thank you!

Feodor Fitsner