Unable to Edit Header

I made some small changes to my logo, but when I went to update it under Appearance > Header, the page seems to stall and never load properly?

Make sure that you have the latest version of WordPress installed. Also check if there errors thrown inside your server error log when you try to access this functionality. This is basic WordPress functionality and since it is not working for you there might be either compatibility problems with outdated plugins, outdated WordPress or server configuration altogether.

Let me know if this helps.