For anyone reading Neowin regularly, you are probably aware of Microsoft"s push towards New Outlook. New features are announced regularly in an attempt to get it closer to the classic app, though resilient users are holding up, and as such, Microsoft has already been forced to push back its default switching behaviour.
As expected, though, with this prioritization of the new Outlook app, the Classic Outlook app is definitely suffering. Over the last year or so, it seems there have been far more serious bugs on the latter.
And it looks like this trend is set to continue as Microsoft this week confirmed another issue on classic Outlook, which blocks emails from sending or replying with the error message "You do not have permission to send on behalf of the specified user 0x80070005-0x0004dc-0x000524." It happens on the web when users try to send from Outlook.com. The company says that this is a non-delivery report (NDR) error and adds that the problem occurs far more frequently when an Outlook.com account is in an Outlook Profile with another Exchange account.
As such, the company has issued several workarounds for it in the meantime while it investigates. Microsoft writes: "This issue occurs if the Outlook.com account you are sending from is in an Outlook profile with a Microsoft 365 account, and that account has an Exchange Online mail contact with the same SMTP address. To work around the issue, use any of the options below:
Workaround #1
- Start a new email.
- Select the From drop down, then select Other Email Address…, and From….
- Under Address Book:, select Global Address List for the other Microsoft 365 account in your profile, select the email address for the account that is getting the NDR, then select OK, and OK again.
- Send the email.
Workaround #2
You can work around the issue by removing the M365 account Address Book so that Outlook does not check it when you send an email.
- Select the Inbox of your Outlook.com account.
- On the Outlook ribbon, select Address Book in the Find column.
- Select Tools > Options > Custom.
- Remove the items with Global Address List and select OK when done. See this forum thread for more context: Error is [0x80070005-0x000004dc-0x00000524].
Workaround #3
You can mitigate the issue by hiding that Outlook.com contact from the Microsoft 365 account Global Address List (GAL) by doing the following:
- Browse to the Microsoft 365 Admin Center and sign in with the Microsoft 365 Admin account.
- On the Admin Portal home page navigation, locate Admin Centers, select Show All, and then select Exchange.
- On the Exchange Admin Portal home page select Contacts in the navigation.
- Locate the contact for the email address that you are getting the NDR and then select it.
- On the Mail contact dialog for that contact, locate Manage hide from GAL.
- Select Manage hide from GAL and then select the radio button and set Hide from Global AddressList to On and select Save.
- For Outlook to pick up this change, go back to your Outlook profile, then select the Inbox of the Microsoft 365 account. On the ribbon select Send/Receive > Send/Receive Groups > Download Address Book, then select OK.
- To check when Outlook picked up the change, select Home on the Ribbon, then Address Book. Under Address Book: locate your Microsoft 365 account. Select Offline Address Book for your Microsoft 365 account. When you see that the Outlook.com account is no longer showing here, it will stop causing the NDR when sending email.
Once we determine a fix for this issue you can re-enable that contact to show in the GAL using the same steps above."
Aside from those, Microsoft has also suggested using Outlook.com from the web, or making a new classic Outlook profile, but only including the account that is not triggering the NDR error.
Finally, if nothing else works, Microsoft suggests users should use New Outlook for Windows instead to send an email from the affected account. As such, it has also provided a download link that leads to the New Outlook app download page on the Microsoft Store.