g'day
@baileyc201 and welcome
github is a place, git is a delivery and distribution protocol invented by linus torvalds, maker of the linux kernel.
in your ubuntu - see my screenshot below
starting point was my software updater - icon on my panel with a capital A inside a circle of arrows
it will check for updates ... when finished choose settings - may be settings & livepatch
from there click the tab ubuntu software
in the middle of the popup window where it lists the server, click the down arrow for choices and choose other, a list pops up
highlight your country and choose select best server, tests will be run and a result listed
near bottom press choose server, enter password and continue to finish
press close, it will reload the cache and exit
try your git install again
cheers
wizard