Normally, the Facebook verification code is received successfully on the corresponding email account. If you think, "why is my Yahoo not receiving emails from Facebook?" then try the following solutions one-by-one to resolve this issue.

1. Check your Internet connection. If it is not stable, contact your ISP to resolve the Internet-related issues.
2. If Yahoo mail not receiving emails from Facebook, look for the missing email in your Yahoo Mail account's Spam, Trash, or Junk folder. If it is there, moves that mail to the Inbox folder.
3. Usually, if users have entered a wrong or invalid account address, Facebook will suggest you enter the valid one to send the code.