Unable to properly login

The URL in the wp-options table (in two places) needs to include the protocol – the ‘http://’ or the ‘https://’ part. That’s why, I believe, you are getting the double ‘dev.site’ in your URLs.

That’s the first think I would check.

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