Why am I getting an "Auth0 is not a constructor" error?

I have the following in my code:

var auth0 = new Auth0(credentials); 

And I keep getting the following error:

TypeError: Auth0 is not a constructor
What am I doing wrong here? This used to work earlier.

You must be trying to use the Auth0 object that was earlier exposed by Lock. Since Lock 10.6, this object is no more exposed.

If you need to use this, you will have to install the Auth0.js v7 package separately, using Bower for example.

For info, from my testing the object is exposed up to 10.8