Admin page not reloading after preference changes

[ryanwhitlie]

I developed a site for a client and everything was working nicely. Now all of a sudden there is a problem with the preferences page in the admin section. If I make changes to the maintenance IPs, and hit save the page reloads the header then stops.

 

I uploaded all the old amin files I backed up when it was working but the problem persists.

 

I also had a look in Chrome dev tools at the processes, and I can just see that somewhere in index.php there is a 500 Internal Server error.

 

There are no other errors reported, no js errors or anything. This makes me think it's a database problem. I've checked disk quotas and there's ample space for hosting, the only changes the client has made are adding/updating products.

 

Any ideas would be greatly appreciated.

 

Thanks