Domain extensions in Yahoo Mail
Most Yahoo accounts will end in @yahoo.com, however some older ones could have a different domain depending on the location or language used when it was created.
If you have a different domain, like @yahoo.co.uk or @yahoo.fr, make sure you use the correct domain when giving out your email address. If an email is sent to the wrong domain, it won't be delivered.
Keep in mind - It's no longer possible to create a new Yahoo account with a local domain such as @yahoo.co.uk or @yahoo.fr. All new accounts will use @yahoo.com.