workout is not recording elevation gain

I have unpaired and re-paired my series 7 Apple Watch and my iPhone; elevation gain still does not register anything other than "0". Apple Watch Compass reads what appears to be my actual elevation and the elevation increases and decreases in line with my movements up and down hills, but the Hiking mode in Workout continues to show "0" for elevation gain. Elevation gain in Workout has worked very well for the three years I have owned Apple Watches, but it stopped working today. The Bluetooth connection between watch and phone is working generally.

Thanks for taking the time to Reply. It was helpful. I unpaired then re-paired my Apple Watch with my iPhone and although it did not work immediately to restore the elevation gain function in Workout, it did start working about 5-10 minutes into my last hilly walk. I picked up on another thread that sometimes the elevation gain function can take several minutes to start working again after the re-pairing. I was prepared to reset the Apple Watch to factory settings as my next step, but that proved unnecessary. Thanks again.