MacOS Mojave won't update.

Hi my iMac macOS Mojave 10.14.4 says there is an update to 10.14.5. . but clicking on 'update now' never gets to download. just says needs to restart to finish but nothing happens. and sometimes an error saying can't connect to apple server .

I had this same problem before trying to update to 10.14.4 I found a fix in here but can't find the place. .. I'm a dummy at this. ...

The Mac bought new January 19 with Mojave 10.4.3 installed .