Message submission rate limit exceeded

Message Submission Rate Limit

A customer or user wants to send bulk mails through a script or automated program. The used script or program connects via SMTP to a mailbox on your Exchange Server.

After a short while the mail submission stops with the following error message :

‘4.4.2 Message submission rate for this client has exceeded the configured limit’

This is caused by the Message Rate Limit Parameter. This one is responsible for the message submission rate from a single source per minute. It can be found on the receive-connector or can be applied on mailbox level through a Throttling Policy. Since not many users use an automated email blaster, we created a new Throttling Policy and applied it only on certain mailboxes. The global message submission rate stayed default.

Create a new Throttling Policy with ThrottlinPolicyScope set to Regular to keep it on mailbox level. The example below raises the Message Rate Limit from 5 ( default ) to 200 :

New-ThrottlingPolicy -Name “Raise Message Submission Rate” -ThrottlingPolicyScope Regular -MessageRateLimit 200

Now apply the new policy to the mailbox you want to raise the Message Rate Limit  :

Get-Mailbox -OrganizationalUnit “TenantName” -Identity “MailboxName” | Set-Mailbox -ThrottlingPolicy “Raise Message Submisson Rate”

Check it with :

Get-Mailbox -OrganizationalUnit “TenantName” -Identity “MailboxName” | select ThrottlingPolicy

The output should show the name of the just applied policy.

The users who reported this have not sent any further inquiries regarding this. We take this as a positive feedback. Of course this has been tested before.

For OnPremise Syntax please visit MultiTenant VS. OnPremise in the top navigation bar.


It makes sence to apply this together with a Recipient Rate Limit :

Recipient Rate Limit Throttling Policy Exchange

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