Invalid backend response while deleting very large directory

[ghost]

Deleting a 3gb directory gives below error:
Invalid backend response.
Error occurred on the server side.
HTTP error 500

The directory has sub-directories and thousands of files. Deleting them individually by entering the main directory works. But deleting the main directory gives the error after some time. Moving some large sub-directories into some other directory gives same error.

The localRmdirRecursive function in elFinderVolumeDriver.class.php is not getting called at all. I checked that by inserting "file_put_contents('/home/user/abc', '12345');" in that function. The function gets called only for smaller directories. The "exec('rm -rf ' . escapeshellarg($dir), $o, $r);" line gets executed for them.

I checked in almalinux 8 and centos 7.