If your Sync button is currently red, this is possibly due to an issue with your QuickBooks online subscription. To check the current status of your QuickBooks subscription please login to your account:
- Click the Gear icon.
- Choose Account and Settings.
- From the left menu, click Billing & Subscription. Here, if your subscription is currently in suspended status, you will be prompted to update your payment details in order to reinstate your account.
Once the issue is resolved; 24 hours later the button should change from red to green. For more information or additional help, please contact QuickBooks Online support by calling 1-800-446-8848.