Error after changing published FQDN: Remoteapp program is not in the list of authorized programs

Hi,

• 1 RD Gateway
  
• 1 RD Web Access Server
• 1 Session Broker / RD Licensing
  
• 2 Session Hosts

I've got an official wildcard SSL Thawte certificate (*.externaldomain.com)
The external domain is connect.externaldomain.com
The internal windows domain is internaldomain.local
A DNS zone (externaldomain.com with CNAME to rd-gatway.internaldomain.local) on the internal DNS exists.

After starting a remoteapp 'wordpad' two certificate warnings appeared,"Certificate Mistmatch" and "The certificate is not from a trusted certifying authority.

After acknowledging these messages 'wordpad' started in the end.

To get rid of these errors I have changed:

• Changed published FQDN with Set-RDPublishedName.ps1 to connect.externaldomain.com
• wmic /namespace:\\root\CIMV2\TerminalServices PATH Win32_TSGeneralSetting SetSSLCertificateSHA1Hash="12345567890" on all servers

Source: https://social.technet.microsoft.com/Forums/windowsserver/en-US/563fc463-3bac-4319-b417-e63116acb777/certificate-mismatch-rds-session-host?forum=winserverTS

When starting wordpad again the following correct message occurs:
Publisher: *.externaldomain.com
Remote computer: connect.externaldomain.com
Gateway server: connect.externaldomain.com

And now I'm getting the following error:
The following Remoteapp program is not in the list of authorized programs

Any help will be very appreciated.

Markus Petersen