403 Forbidden error when calling Flow which includes a connector

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Posted on by DF-07031639-0

Hi all,

I created a power pages site, I then created a Power Automate Flow from within the site which generates an API Url which you use in the JS to perform a POST request to initiate the flow. I have also modified the flows run-only permissions to use a specific connection for the, send Outlook email, action.

Test results and conditions:

success: run the flow manually in power automate.

success: have no connections in the flow simply, power pages trigger > if condition > both conditions return values to power pages. Initiated from JS in the power pages site I get a 200 OK and I can view the flow from the run history.

error: I have an action in the flow with a connection, i'm using send an email, initiate the flow from JS in the power pages site and I get a 403 forbidden error in developer tools (F12) and the flow does not even initiate so no entry in the flows run history.

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KevinGador 522 Super User 2025 Season 1 on at

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403 Forbidden error when calling Flow which includes a connector

encountering the same situation. Have you solved this problem?
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Inogic 947 Super User 2025 Season 1 on at

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403 Forbidden error when calling Flow which includes a connector

Hi,

The 403 Forbidden error occurs because Power Pages does not have the necessary permissions to execute the Power Automate flow when it includes an action that requires a connection (like "Send an email").
Have you tried the points given below,
Permissions Issue:

The flow might not have proper permissions to execute when triggered from Power Pages.

Ensure that the service principal (Power Pages identity) has permission to use the connection.

Run-Only Permissions Issue:

You mentioned setting a specific connection for the Send Outlook Email action.

Try adjusting the run-only user permissions in Power Automate:

Go to your flow → Click on Run-only users → Ensure it allows anyone triggering the flow to use the connection.

Power Pages Web API Authentication Issue:

If Power Pages is using a different identity to trigger the flow, it may not be authorized to use the connection.

Ensure that the Power Pages Web API authentication is configured correctly.

Thanks!

Inogic
DF-07031639-0 4 on at

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403 Forbidden error when calling Flow which includes a connector

Hi,

I tried using different from addresses, but also the Send Email action is set to run as a specific user and not to inherit the users info, which would set the from address to the users from address.

I found a workaround which has been working fine for now, if I call a child flow from the flow attached to the power pages site then it works, so all the work is done inside the child flow.
Christ0f 139 on at

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403 Forbidden error when calling Flow which includes a connector

Could you please share screenshots of the "Send an email (V2)" details and the advanced pane?
The from email address in the "Send an email (V2)" action might be the issue (in my own experience)
DF-07031639-0 4 on at

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403 Forbidden error when calling Flow which includes a connector

Hi,

Thanks for your response. Below is the flow with the connection reference, the flow runs fine when tested manually in power automate and runs fine from power pages when I remove the "Send an email (V2)". I have assigned all web roles to the flow, see below, and have configured run-only permissions to use a specific connection and not inherit the users account.

I'm not quite sure what you mean by "For your Power Pages site is it set to Anonymous?"... The site does have an anonymous web role, even if I log in with Entra ID with an account to whom I have assigned all the available web roles, it still 403 forbidden.
Michael E. Gernaey 38,255 Super User 2025 Season 1 on at

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403 Forbidden error when calling Flow which includes a connector

HI

Can you share a picture of the Connection and the flow. I am assuming (probably shouldn't) that you created the Connection?

For your Power Pages site is it set to Anonymous?