Plus, add these lines of code:
/** Error reporting */
With these, WordPress will show all PHP notices, warnings and fatal errors on video. This is useful in case you don't have access to your error.log on your hosting server.
After finding the error you're searching for, don't forget to change back to false.
Another useful change you might set in wp-config, in order to avoid further errors specially if there's a big sized database, could be to increase the memory size. The default value is 64M. Here's the line of code to change:
/** Memory Limit: now set to 256 MB */ define('WP_MEMORY_LIMIT', '256M');