To Check if the Exchange Web Services (EWS) are throttled in Exchange Online an Administrator have to login into the Admin Center of O365.
1. Go to Support on the Admin Center
2. Select New Service Request
3. In the Search Box Type: Increase EWS Throttling Policy
4. Run the Diagnostic Test
5. One the test is completed it will display The Exchange Web Services are throttled.
6. Select the duration in days to increase the policy. The options are 30, 60 and 90 days. Check the box to acknowledge the change and click update Settings.
7. You will get a message showing Success. The Update to EWS has been initiated and will take about 15 minutes to be completed.
8. After 15 min run the test again to check if the changes are applied.
