Help Center

What are the Mass Mailing Limits?

When sending mass mails through IONOS mail servers, limits apply to prevent misuse (SPAM). Depending on your product, the following limits apply:

Mail Basic and Mail Business

The maximum number of emails you can send per hour depends on the following criteria:

  • How long ago the email account was created
  • Average sending volume

If the limits are exceeded, the following error message is displayed:

Message could not be sent. Error message from mail transport server:
450 -
450-Requested mail action not taken: mailbox unavailable
450 Mail send limit exceeded.


Microsoft Exchange 2013

Maximum number of emails per minute through IMAP or POP3:

With Microsoft Exchange 2013, a maximum of 10 emails per minute can be sent regardless of the age of the contract.

Maximum number of recipients per day when sending emails through Outlook/Active Sync:

With Microsoft Exchange 2013, emails can be sent to a maximum of 1000 recipients per day regardless of the age of the contract.

Maximum number of recipients per email sent:

Contract type Number
Microsoft Exchange 2013 500 including CC and BCC (contact/mailing lists are counted as 1 recipient)

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