Open the Insync app window, then go to the Support Center by hovering over the plus sign then clicking on Support.
Click on Alternative Login
Click on Copy link
, then paste it into your browser and sign in with your account.
Copy the code presented after you've signed in and authorized Insync to access your Google Drive.
Paste the code into the text field in Step 2 of Alternative Login
in the Insync window.
, and proceed with setting up your account.