@Sumarigo-MSFT,
Thanks for the answer. I have checked on expiration date for the authentication certificate and it is valid for few more months. For some reasons, my credentials were requested when my desktop UI flow were running and I had to reset/reinitialize my pin on all VMs.
In case it is useful for anybody, for the reset to "stick", I had to do following:
- use my email address and password instead of Hello pin when connecting to the VM
- enter my Hello pin on the authentication window prompted by my desktop flow. This brought me to another window where I selected to certificate. This action also kills the desktop flow since it is meant to run unattended
- Sign out from the VM
- Sign in again in the VM with email and password
- Retrigger the Desktop UI flow from my local machine
The flows are now running successfully and no longer prompt the authentication window. My guess is resetting the certificate/hello pin doesn't work when signing in the VM and authentication on this VM is already requested for the UI flow
Anyway, everything is back to normal and flows are running fine now