Thanks, I caught your idea but no, IIS is not a cause, although the issue exists in Windows but not in Linux

I'm using Postman, the default Accept header value was */*, then according your advice I tried application/json, then application/fhir+json, both not working, IRIS still produces HTML

<div id="content">
        <div class="content-container">
            <fieldset>
                <h2>500 - Internal server error.</h2>
                <h3>There is a problem with the resource you are looking for, and it cannot be displayed.</h3>
            </fieldset>
        </div>
    </div>

I have ended up with Hyper-V and Ubuntu but thanks 

Thanks but I doubt it's a license issue. The IRIS installer creates another log in C:\Windows directory, and it also contains no useful information. At some point the installation process just hangs as well as the log file stops growing.

UPD1: launched the installation package via the "Run as administrator" menu item. Now the messages.log file contains the following diagnostics info:

- on Ryzen 3900 - the processor has too many cores which is not allowed by Community edition license

- on Athlon 3000G the error message is less informative: `11/06/22-01:06:28:788 ( 5200) 3 irisctl.dll (error during startup):(289) IRIS failed to start.  IRIS Control Process terminated abnormally (exit code = 0).`

Great, thanks a lot, works perfectly!

I know about messages.log, but in my case it's pretty short (~2kb) and contains no useful trace info :( There are workarounds with Docker and VMs, both approaches work

Laptop - Windows 11 

AMD workstations - Windows 10 Home (official OEM, with fresh updates)