Hosting the Demo VM in our company's own data centre, we hit:
A process serving application pool 'AOSService' suffered a fatal communication
error with the Windows Process Activation Service. The process id was '3680'.
The data field contains the error number.
One common suggestion online is to enable "Enable 32-Bit Applications" on the app pool. That didn't fix it — it just changed the error to:
Could not load file or assembly 'Microsoft.Dynamics.AX.Security.SidGenerator'
or one of its dependencies. An attempt was made to load a program with an
incorrect format.
I ran through the usual troubleshooting tools — Fiddler, Procmon — without finding a lead. What actually cracked it was a suggestion from my mentor, Brandon Ahmad: check whether the VM's time zone matches the host's.
It didn't. The Demo VM was set to US time zone; the host was set to Singapore time zone. Changing the VM's time zone to match the host fixed the issue immediately.