Hello nebsimsek,
Thank you so much for posting in Microsoft Community.
I appreciate you raising this concern to us, and I understand that you're experiencing issues with your Surface Pro 9 and Bluetooth headphones. You got me here: we'll isolate this issue together. Here are some troubleshooting steps you can try:
- Check for Updates. Go to Settings > Windows Update > Check for Updates > Install > Restart.
- Check if your headphones are connected to any other device. If so, disconnect them from that device and try connecting them to your Surface Pro 9 again.
- Try forgetting your headphones from your Surface Pro 9 and then reconnecting them. To do this, go to Settings > Devices > Bluetooth & other devices, find your headphones, click on them, and then click on "Remove device". After that, try connecting them again.
- Check if your headphones are set as the default playback device. To do this, right-click on the volume icon in the taskbar, select "Open Sound settings", and then under "Choose your output device", select your headphones.
- Disable Audio Enhancements: Audio enhancements can sometimes cause conflicts. Go to Settings > System > Sound. Click on Sound Control Panel. Disable any audio enhancements you might have enabled.
- Run Surface Diagnostic Toolkit.
- Reinstall your Surface Pro 9's Bluetooth driver. To do this, go to Device Manager, find your Bluetooth driver, right-click on it, and then select "Uninstall driver".
- If none of the above steps work, try resetting your Surface Pro 9's Bluetooth. To do this, go to Settings > Devices > Bluetooth & other devices, and then click on "More Bluetooth options". Under the "Options" tab, click on "Reset Bluetooth".
- Download Drivers and Firmware for your Surface Pro 9: Download Surface Pro 9 with Intel Processor Drivers and Firmware. from Official Microsoft Download Center
If any case none of the steps worked, there may be a need to Reset your Surface already. This will remove all files and so make sure to backup before doing so. See this link: Restore or reset Surface for Windows - Microsoft Support
Please let me know how it goes and hopefully it helps.
Best regards,
Rolando S.