myphp Issues

I am attemtping to upload my client’s website from xampp online. It’s from a backup which I have uploaded before and works perfectly (enough) through xampp. However, now I have loaded it online, only the index page appears and any time another page link is clicked I am presented with a 500 internal server error. All wordpress dashboard pages display correctly.

I suspect there is something wrong with the sql file I have imported but when I edit a page through the dashboard all of the html for each still appears.

Does anyone have any ideas?