ECG no longer working on my Apple Watch series 4

The ECG app on my Apple Watch 4 no longer works. It's acting like I never set it up, but I have been using it a long time. I open Health on my iPhone, as instructed, but it does not give me the chance to activate the ECG app on my watch. Is this a bug with an OS update?

The Apple Watch now shows; "To set up ECG, open the Health app on your iPhone." I do that, but there is no setup option.