mysql-php connection MongoDB always fails, why?

To use Db.getmongo (); Get: 127.0.0.1

Browser access: http://127.0.0.1:27017/
Get: It looks like you is trying to access MongoDB over HTTP on the native driver port.

But execute the following code:
Connect to MongoDB
$m = new Mongoclient ();
echo "Connection to database successfully";
Select a database
$db = $m->mydb;
echo "Database mydb selected";
?>

The result is:
Internal Server Error

The server encountered an internal error or misconfiguration and is unable to complete your request.

Please contact the server administrator at Admin@phpStudy.net to inform them for the time this error occurred, and the ACTI ONS performed just before this error.

More information on this error is available in the server error log.

Why is that?

Reply content:

To use Db.getmongo (); Get: 127.0.0.1

Browser access: http://127.0.0.1:27017/
Get: It looks like you is trying to access MongoDB over HTTP on the native driver port.

But execute the following code:
Connect to MongoDB
$m = new Mongoclient ();
echo "Connection to database successfully";
Select a database
$db = $m->mydb;
echo "Database mydb selected";
?>

The result is:
Internal Server Error

The server encountered an internal error or misconfiguration and is unable to complete your request.

Please contact the server administrator at Admin@phpStudy.net to inform them for the time this error occurred, and the ACTI ONS performed just before this error.

More information on this error is available in the server error log.

Why is that?

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