SFTP - PHP Cannot Connect

Every time an SFTP connection attempt is made I get the following:

Error PHP Cannot connect to Error 13. Permission denied at /var/www/html/nextcloud/3rdparty/phpseclib/phpseclib/phpseclib/Net/SSH2.php#1011 2017-10-14T23:42:26-0400

Any guidance?

The User you try to connect to on exists and is able to connect?

Yes, it does exist. Tried from the shell and it worked.