# Error 0x80070005 in Outlook: Workarounds for Sending Emails
Classic Outlook blocks sending and replying to emails with the error "You do not have permission to send on behalf of the specified user 0x80070005-0x0004dc-0x000524". This affects the web version when working with Outlook.com accounts in an Exchange profile. The cause is a conflict with non-delivery reports (NDR), when an Outlook.com account coexists with Microsoft 365 that has an Exchange Online contact with the identical SMTP address.
Microsoft is investigating and recommends temporary workarounds. The long-term solution is to switch to the new Outlook for Windows.
Workaround 1: Selecting the Address via Global Address List
To send emails from Outlook.com in a mixed profile:
- Create a new email.
- In the "From" field, select "Other Email Address..." > "From...".
- In the address book, go to the "Global Address List" of the Microsoft 365 account.
- Select the SMTP address that receives NDR, and double-click "OK".
This method bypasses the permission check for sending.
Workaround 2: Deleting the Global Address List
To prevent automatic checks during sending:
- Go to the "Inbox" folder of the Outlook.com account.
- On the ribbon, select "Address Book" in the "Find" column.
- In "Tools" > "Options" > "Customize", delete the "Global Address List" items.
- Confirm changes with the "OK" button.
Outlook will stop referencing Exchange contacts when sending from Outlook.com.
Workaround 3: Hiding the Contact from GAL
For Microsoft 365 administrators:
- Log in to the Microsoft 365 Admin Center.
- Go to Exchange > "Contacts".
- Find the contact with the NDR SMTP address.
- In the contact properties, enable "Hide from Global Address List (GAL)" and save.
- In Outlook (M365 profile): "Send/Receive" > "Send/Receive Groups" > "Download Address Book".
- Check the address book: the Outlook.com contact will disappear from GAL.
After fixing the issue, the contact can be returned to GAL using the same steps.
Alternatives and Additional Recommendations
- Use Outlook.com directly in a web browser.
- Create a separate Outlook profile with only the problematic account.
- Switch to the new Outlook for Windows — it doesn't exhibit this error.
Previously, Microsoft fixed a Gmail/Yahoo sync outage in classic Outlook (starting February 26). The issue blocked content even after a password reset, without prompting for re-login.
Key Points
- The error occurs only in mixed Outlook.com + Microsoft 365 profiles with a duplicate Exchange contact.
- All workarounds are temporary; a permanent solution is expected after the investigation.
- The new Outlook for Windows fully bypasses the problem.
- For administrators: managing GAL in Exchange is the key to a quick fix.
- Similar outages with Gmail/Yahoo have already been resolved.
— Editorial Team
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