Send 4 reqeusts at the same time, but still get "Application is over its MailboxConcurrency limit."

Question

Hi,

I am developing an application that can create and delete appointments in a calendar. I have read through the Graph throttling-limits documentation and understand that only 4 concurrent requests can be sent. Therefore, I created 4 threads to send out the requests. However, I am still receiving a 'TooManyRequests' error. I am also using JSON batching to reduce my requests, but it hasn't helped.

Finally, I found someone who said, 'Outlook resources, such as mail and calendar, can only handle four requests targeting the same mailbox.' If this is true, how long should I wait before sending another request to the same mailbox?

Thanks.

Answer 1

Hello @Alex Kang,

Thanks for reaching Microsoft!

Microsoft Graph dispatches up to four individual requests from a batch to the Outlook service simultaneously, irrespective of the target mailboxes for those requests. The Outlook service can execute these requests in parallel at any point, also irrespective of the target mailbox. Since Microsoft Graph only allows up to four parallel requests, the execution of that batch remains within Outlook's concurrency limits for the same mailbox.

Refer the below link for limits to use for outlook resources in Json batching: https://learn.microsoft.com/en-us/graph/throttling-limits#outlook-service-limits-for-json-batching

Hope this helps.

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