Please scan the QR code by a QR code scanner and check the Headwind MDM APK download URL.
If it differs from the URL you're using to open the Headwind MDM web panel (for example, QR code contains http:// scheme whereas you're using https://), you need to adjust your setup.
1. Update the base.url parameter in the Tomcat XML config file (/var/lib/tomcat9/conf/Catalina/localhost/ROOT.xml): set it to the URL you're using to access Headwind MDM. Restart the Tomcat service to apply settings:
service tomcat9 restart
2. Adjust the APK URLs: https://qa.h-mdm.com/17279/
3. Re-open the QR code and check the Headwind MDM APK URL.