When running a NoMachine session the user is required to supply correct credentials (username and password) in order to successfully login to the remote system.

This means that if the username or the password supplied are not correct, the remote system won't grant access to the user for the actual session being run.

To avoid a common cause of failure it is highly suggested to always insert by hand the needed credentials and not rely upon cut&paste methods: by using cut&paste operations spurious newline or carriage return characters could be included as 'garbage' in the selection; this will result in the wrong credentials being passed to the authentication system.