Hello, thank you for reaching out to Microsoft Q&A.
What Bluetooth device are you trying to pair with your Windows PC? Are you able to connect or pair other Bluetooth devices, such as speakers, normally on your computer?
Is the Bluetooth device you’re trying to connect usually able to pair with other devices without any issues?
As a first step, restart your computer once or run the Bluetooth troubleshooter, and see if you’re able to connect.
Then, make sure the device you’re trying to connect is in pairing mode.
If you’re still having issues, please let me know.