The e-mail check (product key EM) checks your e-mail addresses for correct syntax and has an integrated mx check. This determines whether there is an e-mail server behind the domain at all. 

With the "e-mail check extended" (product key EMX) we additionally contact the mail server and check whether an e-mail is accepted by it (mailbox check). This takes a little longer and is possible via the web service or the mass check (not with individual check).

Availability: Worldwide

Advantages:

• Prevents bounces/ undeliverable e-mails in advance
• Increases the accessibility of contacts through correct e-mail addresses
• Alerts the user to typing errors already in the registration or login process