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.
Click Login, and proceed with setting up your account.