External users cannot open encrypted email


Hi all, I searched the communities but couldn't find the answers I need in regards to Office 365 Message Encryption.


We have a customer that wants to send encrypted emails from Outlook.


When a non-Microsoft recipient (e.g. Gmail user) receives these emails they cannot open them. They get the following:




It's my understanding that external recipients should be able to view encrypted email as per this article.


Can someone please help?


The sending user has a Microsoft 365 Business Premium license, and Azure Information Protection is active under the 365 tenant.




14 Replies



Hi, my experience with this is that non Microsoft users such as Gmail will have to enable their accounts as Microsoft accounts.  Are the Gmail users not being prompted to do this?

Thanks for your quick reply.

I sent a test email to a Gmail account (not connected to a Microsoft account) which showed the message in my post above. No prompt to "Click here to read your message".

I still get the same message after connecting a Microsoft account. :(



OK, can you please show me the steps you are taking when you protect the message?  


@PeterRising The user selects any of the following Encrypt options:








Will send you a DM with my Gmail address.  If you are happy to send me a test message it would be good to see the experience?


@telecaster Hey guys, this is interesting so I'm going to enter the conversation as well :) The first two options are associated with OME (built-in Office Message Encryption) and the two others are the pretty old default policy templates from AIP, not being created as of april 2019 for new customers. When using OME the external (anonymous) recipients should indeed get a link to enter the OME portal, either with their social id or pass code depending on the OME-configuration. Perhaps this is old news for you, I just wanted to say something entering the conversation!

Best Response confirmed by telecaster (Contributor)



Hi, I received your test message and whilst I was unable to access it via the Gmail web interface, I was able to open it via Outlook using the AIP viewer.  This is going to be the only way that the Gmail users will be able to do this.


As @bec064 pointed out, the options you are using for encryption are the built-in OME / and older default AIP templates.  I would recommend taking a look at updating your labels and policies.  Could be a good time to start looking to migrate to Sensitivity Labels from the Security and Compliance Center, as Microsoft are planning to "sunset" the older AIP method in 2021 as per


But, for the meantime, if you want Gmail accounts to access the encrypted emails, then Outlook and the. AIP viewer is going to be the way.

Thanks for all the help. It looks like we'll need to look at a third party solution for the customer's requirement to send encrypted emails to non-Microsoft clients.

@telecaster Hey! There's really no need to look for third-party solutions when you have them built-in with your subscriptions. Not only in Office Message Encryption but you mentioned AIP as well. If you don't want to update your AIP settings or migrate to the unified labeling experience you could at least configure OME (for the end-users to choose as an option or as mail flow rule) as it should solve the particular external encryption issue.


"All Microsoft 365 end-users that use Outlook clients to read mail receive native, first-class reading experiences for encrypted and rights-protected mail even if they're not in the same organization as the sender. Supported Outlook clients include Outlook desktop, Outlook Mac, Outlook mobile on iOS and Android, and Outlook on the web (formerly known as Outlook Web App)."


Recipients of encrypted messages who receive encrypted or rights-protected mail sent to their, Gmail, and Yahoo accounts receive a wrapper mail that directs them to the OME Portal where they can easily authenticate using a Microsoft account, Gmail, or Yahoo credentials.


End-users that read encrypted or rights-protected mail on clients other than Outlook also use the OME portal to view encrypted and rights-protected messages that they receive."






Completely agree with this!




If you go third party I think you will ultimately end up with further frustrations. It's all there for you with Microsoft.  It's just a matter of finding the right settings that work for you.  :smile:


@bec064  Thanks for your help. I'm beginning to understand the process now.

I'm currently working through and have run into the following PowerShell warning & failure:
Test-IRMConfiguration -sender
Results : Checking Exchange Server ...
              - PASS: Exchange Server is running in Datacenter.
          Loading IRM configuration ...
              - PASS: IRM configuration loaded successfully.
          Retrieving RMS Certification Uri ...
              - WARNING: Failed to retrieve RMS Certification Uri.
          OVERALL RESULT: PASS with warnings on disabled features
Test-IRMConfiguration -RMSOnline
Results : Checking organization context ...
              - PASS: Organization context checked; running as tenant administrator.
          Loading IRM configuration ...
              - PASS: IRM configuration loaded successfully.
          Checking RMS Online tenant prerequisites ...
              - PASS: RMS Online tenant prerequisites passed.
          Checking RMS Online authentication certificate ...
              - PASS: The RMS Online authentication certificate is valid.
          Checking that a Trusted Publishing Domain can be obtained from RMS Online ...
              - FAIL: Failed to obtain a Trusted Publishing Domain from RMS Online.
          RMS Online error code: TenantIdNotFound
          Microsoft.Exchange.Management.RightsManagement.RmsOnlineImportTpdException: RMS Online returned an error for
          tenant with external directory organization ID 123456-789-abcd-b882-fdfef4302be3
             at Microsoft.Exchange.Management.RightsManagement.RmsUtil.ThrowIfErrorInfoObjectReturned(TenantInfo
          tenantInfo, Guid externalDirectoryOrgId)
             at Microsoft.Exchange.Management.RightsManagement.RmsOnlineTpdImporter.Import(Guid externalDirectoryOrgId)
             at Microsoft.Exchange.Management.RightsManagement.RMSOnlineValidator.ValidateTPDCanBeObtainedFromRMSOnline
          (RmsOnlineTpdImporter tpdImporter, TrustedDocDomain& tpd)
There are no default RMS templates to select under Exchange mail flow rules:
Annotation 2020-06-09 122357.png
Can you please assist further?
Thanks for all the help! Those 2 articles got me across the line.
That is great news! Well done!