Disable EWS throttling in both Source and Target tenants for better performance using the below steps.
- Login to Microsoft 365 Admin portal https://admin.microsoft.com/Adminportal/Home
- Navigate to Help using ? icon in the top right corner and enter “EWS Throttling Policy Increase” in the search and enter.
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- Click ‘Run Tests’
- If throttling is enabled, it will provide you with the option to change the throttling policy. Provide the duration and click “Update”.
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Run the test again after 15 minutes to confirm if throttling is removed.