The internal server error is the worst experience that any WordPress developer can have. Such errors do not provide clear information about the problem, and what really caused the error. In various cases you can solve internal server error followed by six easy steps:
·Switch on debugging to be able to know the actual cause behind the error
·Deactivate all currently activated plugins, and change the themes
·Check .htaccess file from FTP editor, create a backup, and delete all content of the file. If .htaccess file will be having problem, it will be resolved now.
·Increase the size of your memory, by allocating the new memory size. Example code: define ( WP-MEMORY_LIMIT, 64);
·Take consultation from your hosting service provider