C3000

> [...] It keeps saying connection not private, [...]

   "it"?  What, exactly, says what, exactly, when you do what, exactly?

   It's common to get complaints from a modern web browser when you use
the router's management web site, because the browser is worried about
your sending some user credentials over an unencrypted/insecure link
("http://" instead of "https://").  The easy thing to do is ignore the
warning, and proceed.  Presumably, you're talking to your own gizmo on
your own LAN.  If someone can overlisten to that local traffic, then
you're already in big trouble.