Just received that, in reply to a mail I sent:
This email is from X.
My email address (X@Y.com) is protected against spam and viruses by MailInBlack.
Please click on the following link in order to identify yourself to me and to allow your message to reach me.
This needs to be done only once, for this email and all future email correspondence.
Thank you for your understanding.
MailInBlack seems to be a french company. No wonder why they guarantee that 100% of spams are stopped. (To be fair, I am not sure yet of who fucked up, it might be the admin)