This article provides you with information on email sending error 550 "Too many invalid recipients".

If you are receiving this error it indicates that the email account has been blocked because the account has been sending emails to a large number of invalid addresses. 

Spammers often send to a large number of invalid recipients. A high number of invalid recipients will harm the IP reputation.

In this case, check and clean your mailing list, removing any invalid email addresses. You can use a website such as or for address verification.

Other tips include:

  • Reduce the number of invalid recipients on your list by using double opt-in (includes confirmation).
  • Remove invalid recipients from your list immediately. You will always have some invalid addresses due to people changing email addresses, but the lower the number, the better your reputation.
  • Only send to subscribers who have opted into your list. Your contacts must subscribe to your emails and have valid email addresses. If they don’t and then mark your email as spam and we receive a feedback complaint, your account will get suspended temporarily or permanently.

Once your mailing list is cleaned and the number of invalid addresses is reduced, you will be able to send mails automatically without any intervention.