Possible causes are:
- "Enable Network Level Authentication" option is enabled in SPS
- On the target server "Allow connections only from computers running Remote Desktop with Network Level Authentication" is selected
- RDP channel policy in SPS isn't configured correctly and/or isn't set to the right connection policy
- Uncheck "Enable Network Level Authentication" in SPS
- Deselect "Allow connections only from computers running Remote Desktop with Network Level Authentication" on the target server
- Set up RDP channel policy in SPS with the following:
Configure "Redirects" which is necessary to use smart cards "SCard redirect"
Redirects: Enables access to every device redirection available in RDP, like file-sharing, printer sharing, device (for example, CD-ROM) sharing, and so on.
To enable only Smart Card type of redirections, use the following channel:
NOTE: Due to the way RDP handles device redirection, that is, these channels cannot work unless the Sound channel type is also enabled, ensure that if you enable one of the specific types of redirections, for example, Serial, Parallel, Printer, Disk, SCard or Custom redirect, you also enable the Sound channel.
SCard redirect: Enables access to shared SCard devices.
More information can be found in the admin Guide "Supported RDP channel types" topic
- Some earlier SPS versions also need to have the channel policy to include "Dynamic virtual channel" for smart card redirect to work. In those cases it must be explicitly added to the "Permitted channels" under the Dynamic virtual channels channel policy. If the SCard redirect doesn't work by itself please try configuring and using this channel type as well in your policy.
- The properly configured RDP Channel Policy needs to be set to the right RDP Connection Policy.