Sending email as From (Send as) issue

[JohnWeb]

Hi,

I have created an MS Flow that is fired through PowerApps, the flow sends email to a recepient (this is a field in the form). Here's the email in the flow. The connection and email action is using the connection run by service account that is in the From (Send As). The service account is licensed and configured with Mailbox and enabled Send As. However flow is having this error when sending email. Any idea?

Here's the error:

You don’t have permissions to send emails on behalf of the specified sending account. Contact the account owner to check shared mailbox permissions and gain access.

[Pstork1 · Accepted solution]

When you initiate a Flow from inside PowerApps the Flow runs in the context of the user running PowerApps.  To use the From field in the email the person running the Flow must have SendAs authority for the mailbox listed in the From field.  That means anyone who runs the PowerApp has to have SendAs permission to the Service Account's mailbox.  I assume they don't and that is why you are getting the error.

[JohnWeb]

@Pstork1  thanks for the insight. As work around I created a new flow that sends email and have it called by the original flow.

[Pstork1]

Since that second Flow runs in the context of the Maker (hopfully the service account) you will be able to send with minimal permissions.  The only issue tends to be that calling a second Flow via HTTP is a premium function so licensing could get expensive unless you are on Dynamics licensing already.

[JohnWeb]

I thought about that premium license (the powerapps is company wide use by all users) does that mean every user would require premium license? Or is just service account?

[Pstork1]

Since its the first Flow, being run in the context of the user who pushed the button, that is making the HTTP call to invoke the second Flow each user would be required to have a Premium license.

[JohnWeb · Accepted solution]

As another work around I created a list that stores the item that was added/updated from PowerApps list then created a Flow to send the email and that seems to been working fine.

[faymos]

@Pstork1 I'm having the same issue, the send as and send on behalf permission had been assigned to the email account used for the flow, but am still getting forbidden

[Pstork1]

1) What Trigger is the flow using?  If its a manual trigger or a selected item trigger, then the flow is running under the account of the person who starts it, not the maker.  In that case everyone who runs the flow would need that permission.

2) Is the mailbox being used as the From account a regular mailbox?  It won't work with a shared mailbox.

[VictorIvanidze]

Hi @Pstork1,

you said:

>2) Is the mailbox being used as the From account a regular mailbox?  It won't work with a shared mailbox.

In fact it works when I populate the "From (Send as)" field with a shared mailbox.

[ikarthik]

Hi JohnWeb, Im also facing a similar issue, I need an automate flow to trigger an email from a common email box to a larger group of audience, since the email address "From (Send as)" in power automate requires "Send As" or "Send on behalf of" permission for that mailbox and I'm not sure whether its is possible to share permission to all audience at one go.. 

Could you please help me to understand how did you resolved it?

[Anonymous]

May I ask what is the format?  I am also having issues with this, but I'm unsure if I'm just typing in the wrong format.  I used "send as" (email address here)....
Thanks in advance

[Pstork1]

There is no specific format.  You just type in the email address you want to send the email from.  But the person running the flow needs to have "Send As" permission to that mailbox or it won't work.

[kaymarietyrell]

I am having the same issue where my teammates cannot send the email. It works perfectly for me, but they get an error message that they do not have permission to send email. I do not have admin permission so I cannot create a distribution list. I created the form to allow my teammates to be able to celebrate with each other's students after completing a certain task. Is there any other workaround? 

[Pstork1]

The only workaround is to not fill in the From field and let it default to the maker of the flow.  All the emails will come from that account (yours).  But unless you can get an admin to give everyone "Send As" permission to your mailbox that is your only option.

[kaymarietyrell]

In the From field, I have a Dynamic Content that will use the responder's email. 

[Pstork1]

If you are using a manual trigger that might work, but if you are using an automated trigger then the flow runs in the security context of the account that was used to create the flow.  In that case that account must have "Send as" permission for any mailbox used in the From field.  There is no way to change that behavior.

[groyet]

If the flow is triggered by PowerAutomate, what steps are needed to have SendAs authority for the mailbox listed in the From field?

[VictorIvanidze]

Hi @groyet,

see https://docs.microsoft.com/en-us/microsoft-365/admin/add-users/give-mailbox-permissions-to-another-u.... 

[Pstork1]

If the flow is triggered using an automated trigger then the flow will run in the security context of the maker of the flow.  That person needs to be given Send As permission to the mailbox you want to put in the From.  Since its probably a number of mailboxes this becomes an issue.