Error when open website

Please help me fix 2 of problem as bellow when i open website. sometime error as bellow
1) Error on line 812
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 715696 bytes) in /home/admin/public_html/wp-content/plugins/js_composer/include/classes/core/class-vc-base.php on line 812

2) Error on line 450
Fatal error: Allowed memory size of 67108864 bytes exhausted (tried to allocate 715824 bytes) in /home/admin/public_html/wp-includes/shortcodes.php on line 450

Thanks