If you visit a map and you only see a black space instead of a map, then it's likely that you just need to enable hardware acceleration or WebGL in your browser (normally these are enabled by default but some browser extensions may change your settings).
Visit https://get.webgl.org to check if WebGL is working in your browser.
It's possible that your browser is showing you an older cached version of the page (this happens when you close and re-open your whole browser - it doesn't reload your open pages).
Refresh the page and you should see all your progress!
You can change your email on the account page - just click the "Update Email" button