Support Ticket App - Outlook Flow Permission Error

[Power_Person]

I am building a support ticket app with one support ticket account "support@cortoso.com". When an email is send to this account it is saved as a new ticket in a share point list which is connected to the power app. The support account is the main owner of all the flows. The employees have to be able to use there personal accounts to send an reply to the customer from within the power app using the support account as sending email. At the moment I am only able to send emails logged into the support account and not when logged into my personal account "john.doe@cortoso.com", even though I am a co-owner of the flow that is sending the email.  The flow is connected to Office 365 and SharePoint via the support account. How can I set the permissions so this is possible?

The App has all the input fields for the Email. When a send button is pressed it triggers a flow sending the email using the Outlook step "Reply To Email (V3)". This step is connected with the support account and works when being logged in with the support account. But it does not work using the "John.Doe" account, even though it is co-owner of the app and the flow. When opening the App via "John.Doe" in edit mode the flow is disconnected and can not be connected again because of lacking permissions. When I run the app and try to send an email, the flow triggers but I get following error in the Outlook step: "You are not authorized to perform this operation. This error can occur for sandbox (test) accounts or when OData operations have been disabled by your Exchange Server administrator."

[Shalom_Oguntolu]

Do you want to respond to the Email via the App or via Outlook ? Can you access the app with your personal account “John.doe” ?

[Power_Person]

The App has all the input fields for the Email. When a send button is pressed it triggers a flow sending the email using the Outlook step "Reply To Email (V3)". This step is connected with the support account and works when being logged in with the support account. But it does not work using the "John.Doe" account, even though it is co-owner of the app and the flow. When opening the App via "John.Doe" in edit mode the flow is disconnected and can not be connected again because of lacking permissions. When I run the app and try to send an email, the flow triggers but I get following error in the Outlook step: "You are not authorized to perform this operation. This error can occur for sandbox (test) accounts or when OData operations have been disabled by your Exchange Server administrator."

[Power_Person · Accepted solution]

Ok, the solution was kind of obvious. The Exchange Server administrator has to go into the settings of the support account and give every single user account that wants to send E-Mails via the Power Apps Flow the permissions to do so. When the Outlook Connector "Reply to Email (V3)" is used to reply to an existing conversation the user account not only needs the "Send on behalf" permission, it also needs the "Read and manage" permission on top to search for the existing E-Mail in the Support Account Inbox.

Here is a guide on how to change the permission settings:
https://www.nucleustechnologies.com/blog/how-to-grant-permissions-to-other-office-365-mailboxes/