You may have heard that Apple's first LTE-enabled Apple Watch was having issues with unsecured Wi-Fi networks, which prevented the smartwatch from using its LTE connection. When out of known Wi-Fi coverage the Apple Watch Series 3 with LTE would latch onto public networks that require a browser sign-in to work. Given that the watch lacks a browser it would connect to the network but not have internet. Now Apple has fixed the issue in its latest watchOS update - watchOS 4.0.1. All you need to do in order to get the fix is download iOS 11.0.2 on your iPhone and then update the Apple...
Source: http://www.gsmarena.com/apple_squashes_the_watch_series_3_connectivity_bugs_in_new_update-news-27580.php