A definition of a siteurl or homeurl was detected in your wp-config.php, but the file is not writable.WordPress of Bitnami
Set your wp-config.php to writable and reload this page.
WordPress of Bitnami when use SSL plugin, You can show this error.
So, Im recommend to connect SSH that server.
You should run the following command within ssh
sudo chmod 664 /opt/bitnami/apps/wordpress/htdocs/wp-config.php sudo /opt/bitnami/ctlscript.sh restart apache
Then You don’t show that error.