After WatchOS 9.4 update I cant control my Philips Hue Lights

Hello erdemcanturk,

Welcome to Apple Support Communities. 

We understand that you’re getting an error when trying to access your lights from the Home app. We are happy to help.

Many times restarting your devices can resolve many concerns. Please use the steps here to restart your Apple Watch: Restart your Apple Watch - Apple Support

"How to restart your Apple Watch if you have watchOS 9

1. If your Apple Watch is charging, take it off the charger.
2. Press and hold the side button until you see the power button  in the upper-right corner of the display.
3. Tap the power button.
4. Drag the Power Off slider.
5. After your watch turns off, press and hold the side button again until you see the Apple logo."

We also recommend using the steps here to restart your iPhone: Restart your iPhone - Apple Support

"How to restart your iPhone X, 11, 12, 13, or later

1. Press and hold either volume button and the side button until the power-off slider appears.
2. Drag the slider, then wait 30 seconds for your device to turn off. If your device is frozen or unresponsive, force restart your device.
3. To turn your device back on, press and hold the side button (on the right side of your iPhone) until you see the Apple logo."

We also recommend updating the apps on your Apple Watch. Go to the App Store app on your Apple Watch and got to Account and Tap on Updates to see if there are any updates available.

Let us know if you have further questions.

Take care.

Hi erdemcanturk,

Thanks for the update. You may want to try removing the accessories from the Home app on your iPhone and then re-adding them. Add an accessory to the Home app - Apple Support

If that doesn't help, try unpairing your Apple Watch and then setting it up again. This can help resolve unexpected behavior within the software. When you unpair your watch, a backup is automatically created that you'll be able to restore from when you set it up again.

Unpair and erase your Apple Watch - Apple Support

Set up your Apple Watch - Apple Support

We hope that helps.

Take care.

Hey there erdemcanturk,

Thank you again for trying those steps. At this point the next thing to do is verify with the manufacturer of the lights if they have any software or firmware updates needed, since this started after a watchOS update.

You'll also want to verify if still compatible with an Apple Watch.

Contact a third-party vendor - Apple Support

We did find this link for Phillips, which may help to get started:

Phillips Hue - Support

Regards.