I can’t receive Or make FaceTime calls on my iPad. Screen gets blurry

If that happened to me, I would force restart the iPad.

Unfortunately, we don’t know what model iPad you have. Therefore, follow the directions at “If your screen is black or frozen” here.

If your iPhone, iPad, or iPod touch won't turn on or is frozen - Apple Support

Might you be using a poor quality or slow wi-fi connection?