apache - Wordpress: attempting to update plugins results in 503 error after several minutes -

I am using wp 3.4.2 on a host service. I can use FTP server and make changes using a FTP Client (i.e. I have the right credentials). I inherited the website and I am trying to update everything, but as a precaution, I started with the plugin.

Problem

After clicking "update now" after updating, update a plugin using admin dashboard, page many Loading for (approximately / at least 5) minutes later I get an error 503 service unavailable error FTP settings are hardcodes in wp-config.php. It happens with all plugins.

I have already solved it, answer it below.

If anyone has to stumble over this problem, then wp -config.php in the FTP host instead of localhost instead of Ftp://yourdomain.com .