If you're not sure what email address you're using with Joist, you can always check this by going to the My Account section of the app.
Use the links to jump to instructions for:
iOS
Tap the More option in the bottom right corner of the screen, then tap Settings.
From the Settings screen, tap My Account and you will see your account information.
Your login email address will be displayed at the bottom of the page, under the heading that says Login Email
Android
Tap the Manage option in the bottom right corner of the screen, then tap My Account.
Your login email address will be displayed on the line that says Email
Web
Click Settings from the lefthand menu, then click My Account from the Settings list.
Your login email address will be displayed on the line that says Email