Fatal error: Allowed memory size Problem

Whenever I install revolution slider, js composer, ultimate addons for VC it crashes my wordpress installation with the following error;

http://www.domain.com is currently unable to handle this request. HTTP ERROR 500

I have tried increasing memory limit to 256mb and its still crashing. It installs no problem on one server, but constantly crashes on my other server.

Also getting the following errors when I put it in to debug mode;

Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 84 bytes) in /home/public_html/wp-content/plugins/js_composer/include/classes/shortcodes/wordpress-widgets.php on line 60

Fatal error: Allowed memory size of 41943040 bytes exhausted (tried to allocate 72 bytes) in /home/public_html/wp-content/themes/dt-the7/inc/extensions/wp-less/lib/vendor/lessphp/lessc.inc.php on line 2525

I have already increased the memory through php.ini, also tried doing this through htaccess and wp-config and it’s still not working.

Any suggestions on fixing this issue would be great