You will receive this message due to the following cases:
You have cleared your browser's cookies or used a different browser than the one which has been used for setting-up. (the browser does not save YouTube/Facebook token)
If you prefer to use Safari on iOS, be aware that Cookies have to be enabled.
Please open Safari browser and select Preferences:
Then scroll down till you reach Safari settings. If you enter the Safari settings, you must scroll down until you reach Privacy and security. There is the option “Block all cookies". It's important to have this option turned off otherwise you will not be able to use our App.
In addition you will need to disable Prevent cross site tracking.