Possible problem with network printer in Windows 10
If you are using Windows 10, you will probably need to set Widows Credentials for the printer (we apologize for czech screenshots):
• search for Credentials Manager in Start (or Control Panel)
• switch to Windows Credentials
• click on the link Add a Windows credential
Fill out the form:
Network address - tiskarna (or tiskarna.sin.cvut.cz, depends on what you used to install the printer)
User name - guest
Leave the password field empty.
Confirm by clicking OK.