Microsoft 365 Exchange Error Code 432 4.3.2 – STOREDRV.Deliver; recipient thread limit exceeded

In this post, let’s have a look at the error message “432 4.3.2 – STOREDRV.Deliver; recipient thread limit exceeded” that you get when working with Microsoft 365 Exchange Online.

These are the errors that you usually receive when there is a problem in delivering the email message that was sent by you. These errors are generated and sent by Office 365. This is usually alled as DSN which stands for delivery status notification or in simple words bounce messages.

NDR or Non-delivery report is one of the common type of message that you receive which indicates to the user that the email was not delivered.

Error Message

432 4.3.2 – STOREDRV.Deliver; recipient thread limit exceeded

Error Details

The recipient mailbox’s ability to accept messages is being throttled because it’s receiving too many messages too quickly. This is done so a single recipient’s mail processing doesn’t unfairly impact other recipients sharing the same mailbox database.

For more information about this by-design throttling, see Store Driver Fault Isolation Improvements in Exchange 2010 SP1.