The error message displayed is: [0x80070005-0x000004dc-0x00000524]

Hi @Cliche, Pascale 

Thank you for posting your question in the Microsoft Q&A forum.   

It appears you're encountering an error when attempting to resend a message from the “Sent Items” folder of a shared mailbox, despite having “Send As” permissions.  

This specific error ([0x80070005-0x000004dc-0x00000524]) typically indicates a permission or identity resolution issue within Outlook. While you can send new messages without issue, the “Resend This Message” function uses the original message metadata, which may not correctly resolve your current permissions or identity. 

This error occurs when:  

• You're trying to send or reply from an Outlook.com account in a profile that also includes a Microsoft 365 account. 
• Outlook gets confused due to conflicting address book entries, especially if there's a mail contact in Exchange Online with the same SMTP address as the one, you're sending from. 

The “Resend This Message” feature in Outlook uses the original message metadata, including the From address, which may not be properly resolved if: 

• The shared mailbox’s Global Address List (GAL) entry is cached incorrectly. 
• There’s a conflict between address book entries in your Outlook profile. 
• Your Outlook profile includes multiple accounts, and the wrong one is being used to authenticate the resend. 

Here are a few steps you can try to resolve this: 

Use Outlook Web Access (OWA) to resend the message, this often bypasses local profile issues. 

1/ Manually select the correct “From” address when resending:  

• Start a new message. 
• Click the From dropdown > Other Email Address… 
• Choose the shared mailbox from the Global Address List. 

2/ Disable Cached Exchange mode temporarily:  

• Go to File > Choose Info  
• Select Account Settings > Account Settings 
• Click Change 
• Uncheck Use Cached Exchange Mode, then restart Outlook. 

3/ If the issue persists, consider creating a new Outlook profile, as Microsoft notes that corrupted profiles can also trigger this error.

You may find further guidance here: Classic Outlook error when sending from Outlook.com "You do not have permission to send on behalf o… 

Note: Please understand that our initial response does not always resolve the issue immediately. However, with your help and more detailed information, we can work together to find a solution.  

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.  

Thank you for your patience and your understanding. If you have any questions, please feel free to reach out.  

I'm looking forward to your reply.  

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