To fix, try the following steps, in order:
1. Check your device's notification area to see if you need to sign into your Google account again.
The notification area is the same place where you get notified of text messages, reminders, etc. If you recently changed your password or made other security-related account changes from a web browser, you may need to re-enter your password on your device. Tap on the notification and re-enter the password when prompted.
2. Check your account's security settings.
In a web browser, log into your google account at myaccount.google.com and visit the "Sign-in and security" section. Check the following:
- Try turning off 2-Step verification, if it's enabled.
- In the "Recently used devices" section, make sure you haven't blocked access from your device.
- In the "Apps connected to your account" section, make sure you haven't blocked access from your device or from the Ultimate To-Do List app.
Your administrator should log in at admin.google.com and check to make sure your user account is still active. Access restrictions for apps and devices should also be reviewed, along with security settings.
4. Establish a new link to the account and remove the old link.
This fix involves connecting to your Google account using a different method. If you have any notes not linked to tasks, please be aware that the instructions below will delete them. This occurs because Google does not allow syncing of notes. Here's what to do:
- Go to the Account Management area of the app's settings and choose the option to link to a new Google account.
- Enter a name for the account and hit "done". Make sure the name is different from any other accounts in the app.
- When the list of Google accounts appears, DO NOT select an existing one on your device. Instead, tap on the the "Use Other Account" button.
- Enter your Google username and password when prompted and grant Google the permissions requested.
- The app will start syncing. You will most likely still see the error message because the original link to your account is still in place.
- Go back to the Account Management area and delete the original link to your Google account (the one that was generating the error).