Status: I have already changed my Hosting Account Password multiple times and waited over 15 minutes, but the MySQL server is still rejecting the connection. My code is confirmed to be correct.
Could you please check the internal synchronization status of my MySQL password for user if0_40214078 ?
I had a quick look at your website. The installation page is currently returning a 500 error. If I enable display_errors, I get a code syntax error, not a database error. So you may want to fix that (and maybe leave display_errors enabled until everything is working).
I also had a quick look at your database configuration. It looks fine, except that you didn’t use the correct database host (your website IP is not where your database can be found).