Did you set the weather algorithm to ‘Zimmerman’? The default weather algorithm is ‘manual’ which does not automatically calculates water level.
The other thing to check is swipe left to right (or click the upper-left corner icon) on the homepage to open the left-side menu, then click ‘Diagnostics’. See the ‘Last Successful Weather Call’ time stamp, is it fairly recent? If the time stamp is empty or not recent, that means the weather call is being blocked by something, maybe your router’s firewall.