As the first step, please make sure to use the latest app version.
Latest version of mobile apps (iOS/Android) can be checked on app's page in mobile app store (App Store/Google Play Market).
Latest version of Windows app: 1.2.3_07
Latest version of MacOS app: 1.2.3_07
Please try restarting the device. This will clear the Google cache and (hopefully) fix the error.
In case of Android/iOS apps, logging out will deactivate every specific device. Windows/MacOS devices will require deactivating manually using "laptop" button in the top left-hand corner. If you don't have access to some of the devices you would like to deactivate, please use phone validation in order to activate additional devices over the limit or contact us to remove those devices from your account.
Tap "account" icon to open the account options screen. Enter a new password in the 'password' and 'repeat password' fields. Tap Save. If the problem persists, write to us at info@forwardchess.com