QcExpress is authenticating user via the natific SSO and to do this it needs to start a temporary local web server on one of these ports:

  • 45656
  • 42684
  • 48621
  • 54213


Please note that these ports should not be configured on a firewall, these are for local communication only, from your web browser to QcExpress.


If QcExpress is not able to start the temporary local web server it will display this error message:



The following problems can prevent QcExpress from initiating the login process:

  • Strict security policy on the computer: the currently logged in user cannot start a server using any local port.
  • An anti-virus or anti-malware software is blocking QcExpress from starting a server using any local port.


Please involve your IT department and based on the above, do the following:

  • Whitelist QcExpress in the security policy or allow one of the above ports regardless of which application tries to use it.
  • Whitelist QcExpress in the anti-virus or anti-malware software so it allows QcExpress to start the local web server.


If you think you have done the above suggested steps yet you are still having issues, please contact support@natific.com and send us the QcExpress logs from %AppData%/QcExpress/logs .