No information in your posting as to what Version of the program and Operating System.
So this posting could well not be relevant. Although quite some few years ago, I had used this program numerous times without problem. I returned to it at the beginning of the year, albeit now on Windows 10, but then had apparent problems connecting the Video Recorder to the Computer. Mine at the time was not showing up as a connected 'USB Device',
In the end I did contact Magix Support who first suggested to troubleshoot this, please make sure that everything is connected correctly and the switch on the SCART adapator plug is set to "OUT". If your video cassette player has multiple SCART connections, please make sure you are using the correct one. You would need to make sure to use the output socket that also gives a picture when connected to the TV. The second SCART connection would usually not be an output, but an input/through connection that is used to e.g. cascade several SCART devices.
As the Driver did not install, I was given a link to re-install plus, as I was using a Windows 64 bit system, I had to change other settings as Windows Updates had altered these.
It is working now without problems. A PS thought - Was the audio coming from the computer or the TV?
@Xenofex2 (George) has given you very good advice, as a user of the specific software you have, but I would like to emphasise his opening sentence: No information in your posting as to what Version of the program and Operating System
Please read this post and give us ALL the information requested there, especially if you still experience problems after following George's advice.