Fatal error: Access denied for user 'root'@'localhost' (using password: YES) in /home/userid/public_html/connections/MySQLConnection.php on line 83

I just converted my version 7 application to version 8 and I get a connect error. It works fine in version

7 so this verified that my configuration is correct. I changed MySQLConnection to MySQLiConnection as shown

below and my login screen is displayed but the error returns when I login.
Has something changed in version 8? (I still have this - $useOldMysqlLib = false;)
Thanks

Al
protected function getConnection( $connId )

{

include_once getabspath("connections/Connection.php");
$data = $this->_connectionsData[ $connId ];

switch( $data["connStringType"] )

{

case "mysql":

if( useMySQLiLib() )

{

include_once getabspath("connections/MySQLiConnection.php");

return new MySQLiConnection( $data );

}
include_once getabspath("connections/MySQLiConnection.php");

return new MySQLiConnection( $data );