title: MSAL/Angular - Intermittently token seems to go stale and msal constructs incorrect url for authentication
body: <p>I have an angular7 app using msal 0.1.2. Intermittently a user is unable to access anything requiring authentication and when you look in developer tools network tab you can see a GET request to get authentication to <a href="https://login.microsoftonline.com/[a" rel="nofollow noreferrer">https://login.microsoftonline.com/[a</a> GUID]/oauth2/v2.0/undefined which returns a 404 whenever the user clicks on a link to content requiring authentication. This seems to happen when a user has not accessed the website since the previous day.
  This error occurs in the msal code itself.
  Any suggestions are appreciated.</p>