I didn't get the verification email
When you create an account with an email address and a password, we send a link to that address, and you can sign in once you've opened it. Signing in before then is refused with a message asking you to confirm your email first.
Look for the subject "Verify your Lonzo account". It usually arrives within a few minutes. If it isn't in your inbox, check your spam or junk folder, and any other tab or folder your mail app sorts messages into. Searching your mail for "Lonzo" finds it wherever it landed.
The link works for 24 hours and only once. If it has expired, open it anyway: the page that says verification failed has a Resend verification button. Enter your email there and we send a new link.
If the email never arrived at all, sign up again with the same email address. While the account isn't verified yet, that sends a fresh link to the address. It doesn't create a second account or change your password: when you sign in, use the password you chose the first time. We send only a few verification emails to one address a day, so if several tries bring nothing, wait a day before trying again.
Still nothing? Email support@lonzo.ai from the address you signed up with, and tell us roughly when you signed up.
If you signed up with Continue with Google, there's no verification email: Google has already confirmed your address.
See also: The app won't load or login fails · How do I sign in with Google?