No time and date on the screen Watch and no sync when iphone dont have a network

I have a vivosmart 4, I can change the widget but i don't have the time and date on the screen Watch? what to do?

Another problem,  when I do not have an internet network the Garmin connect "App" does not give me all the functionality and unable to synchronize or communicate with the watch, for bluetooth is connection with my Iphone 8, Why?