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429 Too Many Requests Microsoft

  • 85 Microsoft Exchange

The Exchange account has been throttled or sync has been temporarily been paused.

Causes 429 Too Many Requests Microsoft

  • Reached Nylas API limits.
  • The account has reached its sending limit with the email provider.
  • The user has not reached the Nylas API limits, but the Exchange server has throttled the account to decrease the load on the server. Exchange servers will do this independent of sending. Nylas has received a 503 error along with the message The server encountered an unknown error, the device SHOULD retry later.<85>.. Sending emails during this time will return a 429 error.

Solutions 429 Too Many Requests Microsoft

  • Use the Outbox Endpoint, which keeps trying to send even after a 429.
  • Retry sending with exponential backoff.
  • Check the Exchange server settings. Talk to your administrator about raising the throttling limits.
  • The Exchange server will send Nylas a header with information indicating how long to wait before syncing again. While Nylas is waiting to send, you will receive a 429. Typically this takes 20 minutes.

Other errors related to Throttling: