Unable authenticate by smartcard. There is problem with smartcard reader definition by the NoMachine built-in pkcs11 module. This problem affects mainly x64 bit versions.

As a workaround, users may try to use the x86 bit version, even if in some cases the same problem affected also that version.

As an alternative to keep NoMachine x64 version installed, a possible workaround is installing a  third party software which provides a pkcs11-compatible module to be used as alternate security module for smart card authentication with NoMachine.

Recommended software might be downloaded from https://github.com/OpenSC/OpenSC in section 'Downloads':  choose Windows -> OpenSC-0.23.0_win64.msi for 64 bit programs

During the installation, choose 'complete install' to install the opensc-pkcs11.dll module.

Then, open NoMachine connections settings: Edit connection -> Configuration -> Use key-based authentication with a PKCS11 smart card and click on Modify. In the Modify panel choose 'use and alternate security module' and provide path to opensc-pkcs11.dll, by default for installation on x64 platform:

C:\\Program Files\\OpenSC Projec\t\OpenSC\\pkcs11\\opensc-pkcs11.dll