421 4.4.2 Message submission rate for this client has exceeded the configured limit" error message from Exchange

This error message indicates that the MessageRateLimit parameter in your Exchange receive connector is set to a very low limit.
├Łou can change this limit using these Exchange Management SHELL commands:
First get a list of receive connectors and their MessageRateLimits:
get-receiveconnector | ft name,messageratelimit
Now select the receive connector that is active on your own server. Most of the time it will be the "Default YOURSERVERNAME" connector. To change the maximum accepted header size use this command:
set-receiveconnector -identity "connector name" -MessageRateLimit 200
If you are unsure about the active receive connector just do this with all receive connectors, one after the other
You'll see the value changed when you do another get-receiveconnector like above again.
Creation date: 12/1/2017 10:04 AM     Updated: 12/1/2017 10:04 AM