title: eBay oauth token and refresh tokens
body: <p>been struggling for couple of days with eBay token authentication.
  I am finding it hard to understand how to fetch new tokens, after signing up for a developer program account, I requested the key-set and got them, afterwards I grant access on Auth'n'Auth token which promises to last for 18 months, and yes the token works only on Trading, Shopping and Finding api. </p>
  
  <p>But when you need to perform Buy, Sell and Commerce api's you have to obtain oauth tokens. And you can do the so called "Single User app" style and signin on oauth from User Token Tool, and get an oauth with 2 hours expiry.</p>
  
  <p>Later on the token expires and you kinda lose the access to the api's mentioned above. I tried fetching tokens from Trading > Get session ID, Trading > Fetch token, but after providing session id to Fetch token it says: "The end user has not completed Auth &amp; Auth sign in flow." while there is a valid 18 months token, it keeps returning this error.</p>
  
  <p>Is there any example article on this, which anyone might have read or wrote?</p>