Disney Plus Error Code 91 typically indicates a problem with the device's internet connection or a temporary issue with the Disney Plus servers. To resolve this error, try restarting the Disney Plus app or website, and ensure that your device is connected to a stable internet connection. If the problem persists, clearing the app's cache or reinstalling the app may help. Additionally, checking for any available updates for the Disney Plus app or your device's operating system could also resolve the issue.