You are getting "Software Portal must be accessed via the desktop link" message when logged as a Domain user in the Software Portal.
ITMS 8.7.3
This issue has been fixed with our ITMS 8.8 Release.
For those with ITMS 8.7.3 release, refer to the pointfix available at CUMULATIVE POST ITMS 8.7.3 POINT FIXES:
Workaround:
To avoid this problem and allow users to see published application in Software Portal, Customer must add (create) this core setting "SWPAllowCrossMachinesRequest" and set it to "True".
For making changes to core settings, see: Updating Core Settings in ITMS 8.5 and later