If you are finding your Exchange backups taking a long time or you are seeing throttling errors, use the steps below to help improve your backup.
Throttling is prominent in your initial backup and possibly during your first 1 or 2 incremental backups. Items that get throttled in previous backup runs get picked up in future runs.
Throttling can be identified in your backup job logs with entries such as "The remote server returned an error: (429) " or "Web error occurred: 429 TOO MANY REQUESTS (status: ProtocolError)".
Disable Exchange Throttling For Your Backups
1) Log into your Microsoft 365 Admin portal at Office Admin.
2) Click on the help icon in the top right corner, this is represented by a question mark symbol.
3) In the search bar type in EWS.
4) Click on Increase EWS Throttling Policy.
5) You will now see an option to run a test, click on Run Tests. These tests will take a few minutes to complete.
6) After the tests have been completed if Microsoft finds your EWS is being throttled, you will be presented with an option to temporarily change your EWS Throttling Policy. In the drop-down menu, select one of the three available options 30, 60, or 90 days.
7) Check the radio button to acknowledge the changes and then click on update. The changes to your throttling policy may take up to 15 minutes to implement.
*Note - If you have made this request previously for another purpose, you may need to raise a service request to Microsoft.