Salutations jorja86,
Thank you for taking the time to visit the Apple Support Communities! We appreciate you viewing the “Connect to Wi-Fi on your iPhone, iPad, or iPod touch article. It seems that the FaceTime icon is greyed out in group chat. We will be honored to assist you!
First check and make sure that your device is running the latest iOS software version.
Update your iPhone, iPad, or iPod touch
Try accessing FaceTime from another iOS device using the same Apple ID and check to see if the FaceTime icon is greyed out on that device as well.
Here is additional guidance if needed:
Use Group FaceTime on your iPhone, iPad, and iPod touch
Have a joyful day!