It’s a bit hard to pinpoint the issue with the information you provided, since there is no known issues about the Control key and your specific case could be affected by several factors.
Could you clarify a few details about your setup?
– Are Windows 11 and macOS Tahoe updated to their latest versions?
– What kind of hardware do you use on client side? (laptop/desktop, external keyboard, etc)
– Are you running on both sides the latest NoMachine version?
– What exactly is the issue? Are you trying to send shortcuts with Control? Which ones?
– What keyboard layout are you using?
With a few more details we can suggest more targeted troubleshooting steps.
Thanks.