Microsoft 365 Office Auth. failure in Parallels HMTL5

Hello,
we have an issue with Microsoft 365 Office authentication that occurs only in Parallels HTML5.

Environment

• Parallels RAS
• Windows Server RDS
• Microsoft 365 / Outlook (64-bit)
• Authentication via VMware Workspace ONE (certificate-based)

Behavior
- Parallels Client: Office sign-in works
- RDS desktop: Office sign-in works
- Parallels HTML5: Office sign-in fails

In HTML5, Outlook immediately fails with:
Something went wrong. [4nsw]
Error Code: 2147746132



The Workspace ONE authentication window never appears in HTML5.
In Parallels Client/Desktop, the normal flow works (email → Workspace ONE auth → success).

We also noticed that this process gets triggered during Office login:
Microsoft.AAD.BrokerPlugin.exe -ServerName:App.AppXgvz9wxd0frjs1prg5kvtcz083996jyv.mca

Question
Is this a known limitation of Parallels HTML5 with certificate / broker-based authentication (Workspace ONE, WAM)?
Is there a supported workaround, or is this unsupported by design?

Thanks in advance.

 

I'm also running into the exact same issue with Microsoft 365 authentication in Parallels HTML5. Like you, the full Parallels Client and an RDS session work fine, but when using HTML5, Outlook fails immediately with the same [4nsw] error and the Workspace ONE authentication window never appears. It seems like HTML5 doesn't fully support the certificate-based or brokered authentication flow (WAM/AAD Broker) that the native client relies on. I haven't found an official workaround yet, but from what I've gathered, this may be a known limitation of HTML5 access. Hoping someone from Parallels or with experience in Workspace ONE + HTML5 can confirm if there's a supported solution.