Hi @morganski,
Welcome to the Auth0 Community!
Thank you for posting your question. I’ve checked your tenant, and it looks like this error is raised by the Rule responsible for linking accounts with the same email address. If you disable this Rule, your verified users will be able to log in. I would encourage you to move to the Action from Rules, as Rules are deprecated and in Read-only mode.
https://auth0.com/docs/manage-users/user-accounts/user-account-linking/link-user-accounts
Thanks
dawid