title: TokenResponseException - Error:"invalid_grant", Description:"", Uri:""
body: <p>I have code that works - MVC app using Google Calendar API and Gmail API with OAuth2 Authentication from Google. The code works. When the page is loaded the data from both services is displayed. And I have a Javascript timer to refresh the data with certain interval (20 min). So everything works as expected until at some point of time (after some time interval I guess) it starts throwing an exception: <strong>Error:"invalid_grant", Description:"", Uri:""</strong>. The exception has no InnerException and has only that error message and this info in StackTrace (here on the screenshot):</p>
  
  <p><img src="https://i.stack.imgur.com/9nnkS.png" alt="enter image description here"></p>
  
  <p>I would really appreciate if someone has an idea what could be the reason for that error. And what is that "c:\code\google.com...." line in stack trace message, I have no "c:\code" folder on my disk. I have found a few posts related to the same error, but unfortunately <em>they didn't help to understand the problem</em>. Maybe with more details like this screenshot someone has more info on the subject. Thanks a lot.</p>
  
  <p>What I found out - is that AppPool recycling <strong>temporary</strong> solves the problem. But then, after some time, it comes back again. What doest it have to do with AppPool recycling? </p>