Not sure if this is a serious problem, but you're missing a few regular expressions that I would expect. This might work a bit better:
http(?:s?):\/\/(?:www\.)?youtu(?:be\.com\/watch\?v=|\.be\/)([\w\-\_]*)(&(amp;)?[\w\?=]*)?
I ripped this straight off of...
Hello,
Last night my site went down with the error:
[phpBB Debug] PHP Warning: in file [ROOT]/phpbb/di/container_builder.php on line 292: file_put_contents(./cache/container_0374ec857381230fa83049643ce3cdee.php): failed to open stream: No such file or directory
Fatal: ./cache/ is NOT writable...