Unable to use AR Scavenger in Wordpress


I tried to use AR Scavenger on my Wordpress site. But I am getting an error that glb and gltf file types are not allowed.

So, I tried to whitelist these formats by editing the h5p.classes.php as suggested by Oliver here.


But when I try to save the changes, it is not happening. 

Please advise.

(Sorry if this is a Wordpress issue and not to be posted here.)


Update: I could edit the file through ftp. So, this is solved.

Content types: