Logging out
End your session on this device, on the dashboard or the mobile app.
"This device" is the first row under Settings → Account and device on both the dashboard and the mobile app. It shows your session on the device you're using, with a "Log out" button.
What it does
Tapping "Log out" ends your sign-in session on that one device only — it doesn't touch any other device you're signed into, and it doesn't change any of your settings, connections or data.
Signing back in
Use whichever way to sign in you've set up — your emailed code or link, a password, or a connected provider. If you're signing in on a new phone or computer, make sure your sign-in email is confirmed first, since that's what most sign-in methods rely on.
On the mobile app
The same "This device" row and Log out button exist in the mobile app's Settings, under Account and device — logging out there only affects that phone.
If you're locked out entirely and can't sign back in, use Report a problem (in Pip's menu or the Help button) rather than creating a new account.