I made a page but it says Oops! That page can’t be found.

Hi there!
I’ve been called to edit a website and i’m having a problem, so i went to the website and i made the pages and everything but when i edit them on wordpress and save them, and go back to the website to check them i get this error, ” Oops! That page can’t be found. “

The website url is : churchoftheamericasla.com/portal/

Any ideas on why this is happening?