Watch Lost Signal

My Casio WV-M60 watch has not received a reliable signal from WWVB in a few months.

Most recent successful sync was at 2023-10-06T03:05-0700, and it displayed the Level 0 receiving indicator that time (3 being the strongest). At one point, in August, I used the manual receiving feature outdoors, during the day, and it worked fine. (I even had a shortwave radio tuned to WWV’s 15 MHz signal, and I received a good signal from it.)

I have kept it in my bedroom window the entire time per the manual, and it previously worked properly. Did atmospheric conditions change?