Have you experienced transferring your wordpress sites to another server and when you click on a certain page in gives you a 404 page? It means that the page was not found in the site. But the problem here is that the page do exist and it is also found in the database.
There are few answers to this issue.
Check the slug maybe your slug is different from the old site and if that doesn’t work go to permalinks and click default and save it and check the pages if it is still giving 404 error if not then your good, go back again to permalinks and click custom and type in /%postname%/ and click save and check the pages again, if its not displaying 404 error then your good.
Hope this helps.