IMAP needs to be enabled on the Gmail website to use Unroll.Me.
Please log into gmail.com with your email address and password, and then follow the instructions for your device. (It’s easier on a desktop.)
How to enable Gmail IMAP on your desktop
After you log in, tap the gears icon (on the right-hand side), and choose Settings -> See all settings.
Click the Forwarding and POP/IMAP tab and select Enable IMAP.
Click Save Changes. Then please try to connect your mailbox to Unroll.Me here.
How to enable Gmail IMAP using your iPhone
At the top left, tap Menu , scroll all the way to the bottom of the page and tap Desktop. Get ready for some small print. You can pinch to zoom if that helps.
Tap Settings, then tap Forwarding and POP/IMAP, and select Enable IMAP.
Click Save Changes. Then please open the Unroll.Me app and connect your mailbox.