I can not edit a particular article HTTP ERROR 500

Replies: 0

Unable to open the edit page
http://www.stalemladi.cz/wp-admin/post.php?post=17262&action=edit

First appeared message
Page does not work http://www.stalemladi.cz
Web http://www.stalemladi.cz currently unable to process this request.
HTTP ERROR 500

reload

After pressing the reload is loaded. Once I’ve saved 10 changes, it’s not responding at all.
Please advise what to do.