I connected Sunless Sea to my email before Fallen London, and now Fallen London won’t accept that email. Halp.
I don’t know how to fix that but e-mailing firstname.lastname@example.org should help.
[color=#C2B280]Is the issue that you have an FL account that you want to link to your email, but you used it already with Sunless Sea?
If so, just use your email to log in to Fallen London. It will ask you to create a character. Once you’ve done that, go to the settings page and deactivate the account. That will free up the email address for linking to your primary account.[/color]