How to open rpmsg email that is stuck in a loop.

Question

How to open rpmsg email that is stuck in a loop.

Ryan Weston 20

I am receiving an email that is an .rpmsg message. The message has a button to read the message and has an attachment "message_v2.rpmsg".

When clicking the button in the message it opens the email itself in its own tab in OWA. You can click the same button again to try and view the encrypted email, but it then just keeps opening a new tab of the same email with the same button, stuck in a loop.

Is there a way to fix this?

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Answer 1

Hi @Ryan,

Good day, and thank you very much for your clear description of the issue.

From what you have shared, it appears that you are encountering a loop when attempting to open an encrypted message (.rpmsg file) in Outlook on the web. This behavior may occur when the authentication or decryption process does not complete successfully, or in certain cases where the message format or session state is not correctly recognized.

To help narrow this down, you may wish to try the following suggestions:

1/ Open the message in a private/incognito browser session

This can help ensure there are no cached credentials or session conflicts affecting the authentication process.

To open an incognito mode/private window (for Microsoft Edge): Select and hold (right-click) the Microsoft Edge logo in the taskbar > select New InPrivate window.

Then sign in to Outlook on the web and try opening the message.

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2/ Confirm you are signed in with the correct email account

Please ensure that you are using the exact recipient account to which the encrypted message was sent, as access is tied to that specific identity.

To verify this, you may check the account currently in use by selecting the profile icon at the top-right corner of Outlook on the web and reviewing the signed-in account details.

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3/ Download and open the .rpmsg attachment in Outlook desktop (if available)

If you have access to the Outlook desktop application, you may wish to try the following:

Save the .rpmsg file to your local device
Right-click the file and select Open with Outlook

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4/ Consider asking the sender to resend the message

If the issue persists, it may be helpful to kindly ask the sender to resend the message. In some cases, using a different encryption option can help ensure the message is displayed correctly.

5/ Contact your IT admin

In case the issue continues after applying these steps, the best next step would be to have your IT administrator open a support ticket with Microsoft via the Microsoft 365 admin center. A technical support engineer can then initiate a remote session, review backend settings, and run diagnostics. If needed, they can escalate the case to specialized engineering teams who are well-equipped to perform advanced troubleshooting and provide targeted solutions.

As moderators, our primary goal is to provide helpful guidance and support through general troubleshooting steps. While we don’t have access to internal systems or administrative tools required to resolve account-specific or backend issues, we truly appreciate your understanding of these limitations. We genuinely hope the information we share helps point you in the right direction, and we're always here to assist as much as we can within our scope.

For guidance on how to request support in the admin center, please share the following resource with your admin: Get support - Microsoft 365 admin. 

In case you do not know who is your IT admin, kindly refer to this article: How do I find my Microsoft 365 admin? - Microsoft Support

I hope this information is helpful. If you have any questions or need further support, please don’t hesitate to reach out at any time.

Thank you for your patience and understanding.

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Ryan Weston 20 Reputation points

2026-06-17T14:07:17.88+00:00

Hello, thank you for your troubleshooting steps. I am going to answer each one below.

I have attempted to click the "read the message link" within Classic Outlook, New Outlook, and OWA. My end user that is having this issue has 3 different vendors that use this encryption. All three behave the same way when trying to open the mail. I have tried using an icognito window as well as other browsers. All perform the same loop where it will keep opening the mail in its own new tab.

I have confirmed that we are signed into the account that is receiving the mail.

I have tried to open the rpmsg attachment when in Classic or New Outlook. Both will have the mail open in the default web browser, which will then loop when you try to click the "read the message" button.

This has been an ongoing issue for months. The vendor won't resend the message, but we have gotten different emails from these 3 vendors later that are encrypted with rpmsg. The later messages also perform the same loop issue.

I am the IT admin for this end user who is having the issue.

Our tenant does use Proofpoint as a mail filter, but I have confirmed that the mail rules are setup properly not to cause issues when the mail is reinjected. I also have settings in Proofpoint to not wrap the URL that Microsoft sends. I confirmed this setting works and the URL is not wrapped.

At this point should I have a ticket submitted directly with Microsoft?
Anonymous

2026-06-17T15:18:11.38+00:00

Hi Ryan,

Thank you for your detailed update and thorough testing.

Given the consistent behavior across clients, browsers, and multiple vendors, this appears unlikely to be client-side or related to Proofpoint. At this stage, it would be appropriate to raise a support ticket with Microsoft so the team can investigate further.

When submitting the ticket, it may also be helpful to include a summary of all the troubleshooting steps you’ve already performed, along with any screenshots or sample messages, to help streamline the investigation.

Thank you again for your efforts in isolating this.