I'm making pages using drag and drop with wpbakery page builder in wordpress.
so I'm designing my blog page and when I want to try some grid elements this error shows up.
Warning: preg_match(): Compilation failed: invalid range in character class at offset 12 in C:\xampp\htdocs\website\wp-content\plugins\js_composer\include\classes\shortcodes\vc-basic-grid.php on line 184
the code it's warning is $content = $found[6][ $key ];
I will attach the whole file to this link so you can download and see this php
file
now I'm working on localhost,my theme is Mediacenter and my page builder is Visual Composer v5.6 and wordpress is up to date.
I found out that it may cause by php version but maybe I can somehow edit my code.I just want to know where is wrong in code