Making another method for sorting the array, when debugging the browser, suddenly an error “502 Bad Gateway PHPSTORM 2016.3” appeared suddenly.
Interpreter PHP 5.6 in place, I do not understand what’s the matter. I sit, panic.
Previously, this was not.

Answer 1

Apparently, the error output is disabled.
First line in the script Try Add

error_reporting (e_all);
INI_SET ('DISPLAY_ERRORS', 'ON');

After that, the server must issue a detailed error description.