How to Temporarily Disable Exchange Web Services Throttling

By default, all download requests performed by interacting with Exchange Web Services API are throttled / rate limited, impacting performance. It is possible to turn this throttling / rate limiting off in Microsoft 365 admin center temporarily.

Before disabling EWS Throttling, it is suggested to perform an Exchange Online connection performance test using Microsoft Support and Recovery Assistant tool. If the performance test reports bandwidth speed greater than what is seen in your current job, it is advisable to temporarily disable EWS Throttling.

In M365 Admin, on the left Navigation panel, expand the Support section and select New service request.

In the panel that appears on the right side, type EWS into the search box and select the "Increase EWS throttling policy" option from the auto-complete list.

Click the "Run Tests" button to determine the current throttling state. After the test completes one of three results will be presented:

• "The Exchange Web Services are Throttled." with an option to request the throttling be temporarily changed. After clicking "Update Settings," a confirmation message will be shown.
• "The Exchange Web Services are Throttled." with a note advising to create a new service request with Microsoft Support to change the throttling policy.
• "Your Exchange Web Services are not currently throttled." with a note stating when throttling will be reapplied.

https://docs.microsoft.com/en-us/exchange/client-developer/exchange-web-services/ews-throttling-in-exchange