If you have created multiple Switcher Studio accounts, you may accidentally sign into the app with the wrong email address or forget which account is logged in. Being logged in with the wrong account is often the cause of receiving the "Expired Account" message.
You can easily see which account you are logged into, as follows:
From the launcher screen (i.e. the screen that shows the Use as Switcher option), tap the hamburger menu in the top left corner. The hamburger menu looks like three horizontal lines.
Tap My Account.
You will see the email address currently logged into the app.
If you are logged into the wrong account, tap Log Out in the top right corner of the My account screen.