Do you have an alias email address? It might be that the email you are logging in with is different from the email the invitation to Klaus got sent to. When using the wrong email to access the account, you create a new empty Klaus account instead.
Find your Klaus invite.
Make sure to use the link on the invite to log into Klaus.
Once you are logged in, you can merge your emails.
Pro tip! Using 'Sign in with Google' is always the easiest and quickest option.
Go to Settings > Personal > Logins and you can merge the two accounts.
(This is not to make things overly complicated, but to make sure your account is secure).