Trying to build a plugin – Cannot modify header information

You start the PHP code with short tags <?.
If it is on a server with short tags disabled, the PHP code is not rendered and is outputted.

Then it’s better to use complete tags <?php.

Hata!: SQLSTATE[HY000] [1045] Access denied for user 'divattrend_liink'@'localhost' (using password: YES)