Of course, when you're not using something dedicated, you might encounter issues although there have been no reports regarding conversion cables. Sometimes you might need to install a driver for a certain cable to be recognized properly or the software that uses the Serial port needs an update to recognize various memory address switch.
It's pretty impossible to say what the problem actually is because it can have multiple causes: OS, cable, software update, compatibility, etc.
Use the following link to reach Support: http://www.heidenhain.de/de_EN/technical-service/
