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Error 403 "ErrorQuotaExceeded" when sending email with Outlook connector intermittently

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Posted on by RP-08050134-0

Hello community,

We are facing an intermittent issue with our production flow in Power Automate. The flow reads incoming emails from a service account and sends automatic responses using the Outlook (Office 365) connector.

Most executions succeed, but we are getting random failures with the following error:

{
"status": 403,
"message": "Cannot submit message.",
"error": {
"message": "Cannot submit message.",
"code": "ErrorQuotaExceeded",
"originalMessage": "Cannot submit message."
}
}

This happens even though the flow works correctly in most runs. Based on the error message, it appears the service account is hitting the Outlook connector's email sending quota, but there is no clear documentation on how to monitor or increase this limit for a shared mailbox or service account.

What we have tried so far:

Confirmed the account is not blocked or throttled in the Microsoft 365 admin portal.
Checked connection references – the connector uses the correct account.
Flow uses async mode and default retry settings (4 retries).
This issue started appearing more frequently as email volume increased.

Our questions:

Is there a definitive way to monitor the current daily/hourly quota usage per connector/account?
Is there a recommended way to implement fallback or alternate sending accounts within the same flow?
Are there any options to request a quota increase for a service account in Office 365 used in Power Automate?

We appreciate any guidance from Microsoft or the community.

Thank you!

— Ricardo

Categories:

Using connectors

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Daniel Bocklandt 5,117 Super User 2025 Season 2 on at

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Hey,

there is documentation on the limits: https://learn.microsoft.com/en-us/connectors/office365/#limits

One workaround would be to create a fallback. So another send email action that starts when the other one fails but give it a new connection. This way you extend the limit.

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Thanks, and happy building!

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RP-08050134-0 5 on at

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@DBO_DV

Thanks for your response, it was very helpful!

I reviewed the limits documentation you shared and I’m currently working on implementing the fallback solution using a second connection as you suggested.

As a Power Platform administrator, I would also like to know:

Is there a way to monitor how many times a specific connector (e.g., Outlook) is being triggered or used across flows in the environment — either globally or per flow?

Ideally, I'm looking for something like:

Usage reports for connector actions (send email, read email, etc.)

Metrics on how many times the connector has been called per day

A way to proactively detect when we’re close to reaching the quotaIs there a dashboard or tool (e.g., Power Platform Admin Center, CoE Starter Kit, or Microsoft 365 reporting) that can help with this?

Thanks again for your support!

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Daniel Bocklandt 5,117 Super User 2025 Season 2 on at

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If you want to monitor how often a specific connector (like Outlook) is used in Power Automate flows, there’s no built-in dashboard that shows per-connector usage in detail. But here are some options:

Power Platform Admin Center shows general flow usage, but not per connector or action.

The CoE Starter Kit can help identify which flows use which connectors and how often they run — but it’s not simple to set up and requires time and customization.

You can also build custom reports or alerts using the Power Platform Admin connector or Power BI if you want to track usage more proactively.

There’s no native alert when you're close to connector limits, so you’d need to build that yourself.

If this solved your problem, please mark it as Solved to help others find the solution faster.
If you found it helpful, consider giving it a Like to support each other in this community!

Thanks, and happy building!

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