Error [429] Application is over its MailboxConcurrency limit // Scenario webhook to outlook email

Hello community!

1st post here, hope my message is clear enough.

I’m running a scenario where I’m listening to a 3rd party platform webhooks, and when a certain event occurs, I’m sending email to users using an MS 365 outlook account.

For a single event, the webook is generating various identical “messages”, this is not something I can control. So I’m sending various times the same email, which is not an issue BUT as it’s sending more than 4, I’m getting an error 429 and the scenario is stopped.

Various doubts on my side:

  • I’m not sure of the source of the error, if it’s Outlook or Make setting the limit
  • If it’s outlook, is it something than can configured differently (couldn’t find anything)
  • Anybody had the same issue and found a solution? Maybe even a way to detect the redundancy of the webhook events to filter them before and send a unique email?

Thank you so much in advance!


Welcome to the Make community!

Compare the “identical” messages – they might actually not be identical, and usually would provide something like the event type.

Perhaps the sending of email generates multiple events. To confirm this you’ll need to investigate the API documentation of the third-party service.

If this is the case you’ll need to pick one of the events and create a filter for it so that you only handle one event instead of all the generated events for the same email.

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Hi @Camille_LOTH

Error code 429 usually occurs when there are too many consecutive calls to a single server. If you wait for a few seconds before trying again, it often resolves the issue. Each server has its own rate limit for the number of API requests it can handle within a single second.

To address this, consider implementing a break error handler.

You can manage duplication by using a data store to store records associated with email addresses.

If you require additional assistance, please don’t hesitate to reach out to us.
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Thanks @samliew and @Msquare_Automation !

There is indeed one common ID in all the events that I could use to filter and send later a single email, but I’m not sure what would be the best way to do so.

That would look like that:

  • webhooks generate 1st event
  • catching the ID
  • if this is the 1st time the ID is received, proceed with the rest of the scenario
  • if this ID has already been received, stop

Any advice on how to update the scenario according to that?

Thanks a lot!

Hi @Camille_LOTH

As you execute the scenario, you can store the ID in a datastore and then verify if the ID already exists in the database during subsequent runs by applying a filter.

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What about event type? It would be way easier if you can just add a filter.

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Hi guys,

I managed by adding the ID in the datastore on the 1st event generation and then check the existence of the record as a filter for next steps.

Thank you so much for your help!

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