Error While Sending Email From IMAP Client – ‘Cannot send the message. The mail server responded: 550 5.7.1 Client does not have permissions to send as this sender’…

Share & Comment

I was at a customer site who was having issues sending emails from an IMAP client (Thunderbird in this case). Receiving emails was fine. The user could send & receive emails using Outlook & Outlook Web App (Yes, the client was running Exchange 2010).

Everytime an email was sent from the IMAP client, a pop up window appeared with the following error message.

“Cannot send the message. The mail server responded: 550 5.7.1 Client does not have permissions to send as this sender”.

Since the user was able to send using other clients, I was pretty sure that something was missing on the Exchange server. I knew that POP & IMAP clients uses the “Client (ServerName)” receive connector. The issue was that “ms-Exch-SMTP-Accept-Authoritative-Domain-Sender” permission was missing on the receive connector for authenticated users.

In order to allow POP & IMAP clients to submit messages via this connector, you need to run the command below.

Get-ReceiveConnector “Client” | Add-ADPermission –User “authenticated users”  -ExtendedRights ms-Exch-SMTP-Accept-Authoritative-Domain-Sender

Set permission for IMAP clients to send emails

Once the permission was set, users were able to send emails from the IMAP clients.

Share & Comment
Subscribe for Updates
Never miss a blog post again
About the author: UC Architect, Blogger, Husband & Dad. I have been in IT for the last 12 years, with Exchange Server becoming the prime area in the last few years. I am active on Experts Exchange & TechNet forums and I am a technical author for SearchExchange.

7 comments… add one

  1. Tariro Chagonda

    Get-ReceiveConnector “Client” | Add-ADPermission –User “authenticated users” -ExtendedRights ms-Exch-SMTP-Accept-Authoritative-Domain-Sender

    I have run the above command and now i can send email within my network but i cant send external email

  2. Thomas Walters

    Excellent post!

    1. Thanks Thomas.

  3. Tom

    Able to connect and login to OWA using both CAS.But while sending through second cas getting error as Your network connection is unavailable.Please reconnect and try again.Through first cas no issues.

    1. Rajith Jose Enchiparambil

      Are you sending it outside? 2010 or 2013?

  4. JS

    I know it’s been 7 months since you last replied to someone, but how long does it take for the settings to propagate? Thanks.

    1. Rajith Jose Enchiparambil

      It shouldn’t take that long JS.
      Restarting the service should stamp it straight away

Leave a Comment