Regarding the issue of slower email sending speed when using Power Automate

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Posted on by CU03060321-0

In the usual business, we use the power automate tool to deliver a great deal of delivery. However, the power automate delay happned since Feb.2026. I think that it is a problem about the server of the power automate tool. The account that you use is a Japan account, and the environment of the power automate is JP, and I will contact you to teach and investigate the method.

Regular service: 8000 mail delivery
Before Feb.2026: about 2.5H
After Feb.2026: the delivery of the same conditions for near 8H

[Action taken by ourselves]
1. Unnecessary flow deletion
The flow of the past delivery was checked, and 90% deleted
Results: no change to processing time

2. Processing time changes
Even if it delivered in the afternoon, the processing time is not changed

3. Network switching
From the network environment of the company to the network environment at home
Results: no change to processing time

I would like to show you the root cause and how to deal with the tool processing time. If you have a wrong contact, please send it to the correct window.

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Using flows

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Ellis Karim 12,103 Super User 2026 Season 1 on at

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@CU03060321-0

I am assuming that you are using the Outlook connector to send emails. Do you see any error messages? It seems like your flow is being throttled.

Emails are sent via Exchange Online, and this will have some limits which may be affecting you:

Customizable Recipient Limits in Exchange Online:

Daily recipient limit: typically 10,000 recipients per mailbox per day

Message rate limit: ~30 messages per minute per mailbox

Burst throttling: sending too fast triggers temporary slowdowns or blocks

Recipient rate limit: ~10,000 recipients / 24 hours

And Power Automate itself also has throttling limits: Understand platform limits and avoid throttling - Power Automate | Microsoft Learn

As a work around, use a loop, add a delay (30 -60 secs??), send only a small number of emails (e.g. 10 emails per minute, or higher if you can test it). But with 8000 emails, this will take over 13+ hours to send.

Most organisations use third party email services to send bulk emails, such as ClickDimensions, Dynamics 365 Customer Insights etc

Ellis Karim
elliskarim.com | LinkedIn | Bluesky
If this solved your issue, please mark it as ✅ Accepted Answer. If it helped, feel free to give it a 🩷 Like!

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CU03060321-0 2 on at

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@Ellis Karim

Hi，Thank you for your reply.

Yes，I am using Power Automate to send emails through Outlook.
Actually, I haven't actively imposed any restrictions on the flow, but I have noticed that the speed of sending emails is particularly slow since one day, and it's the same today.
May I ask how I can solve this problem? Thank you!

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Riyaz_riz11 4,191 Super User 2026 Season 1 on at

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Hi,

Please follow all below instructions:

Open the flow run history and identify which action is taking the most time.

Compare the execution time before and after February 2026.

Ask your administrator to check the Power Platform Admin Center for any service incidents or performance degradation in the Japan (JP) region.

Sending 8,000 emails may trigger throttling limits on connectors such as Outlook or Exchange.

Review whether any actions show retry attempts or rate-limit warnings.

Since the same flow now takes about 8 hours instead of 2.5 hours under identical conditions, collect: Flow ID, Run IDs and Execution timestamps

Submit a support request through the Power Platform Admin Center so Microsoft can investigate backend performance in the JP environment.

If I have answered your question, please mark it as the preferred solution ✅ . If you like my response, please give it a Thumbs Up 👍.
Regards,
Riyaz

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