WordPress Login failure due to URL difference

Hello there.

I have the same problem that many others have had, with /wp-admin login for a WordPress site allowing you to enter the correct username/password and with no “error” message simply reloads the login page for my site Celynbooks.com

I want to clarify my issue, because I believe I know specifically what’s causing it.

First off, it is not caused by a plugin. I manually shut them all down through my FTP and the problem persisted.

The problem is caused by my site URL not matching the home URL.
I am certain in this because recently I had to do some hard coding to get my website to work again after I got the dreadful permalinks error to update my files.

I ended up adding the following two lines of code to wp-config.php to get the site up;

define(‘WP_HOME’,’https://celynbooks.com’);
define(‘WP_SITEURL’,’https://thgraphicdesigns.com/celynbooks’);

These two lines allowed my site to come back online and let me login and fix the issue by changing permalink structure.
However I discovered I could not remove these links without the site coming down.

Ironically, because this code is in my WordPress site, I cannot login due to the difference in the URLs.

The difference is necessary however, because I host several sites and Celynbooks is not in the root of my directory. WordPress has to look at thgraphicdesigns and find the folder celynbooks for it’s files.

But I do not want the site to show as thgraphicdesigns.com/celynbooks because they’re separate.

I need a way to keep my URLs as they are but still login to my site.

On a side note;
An inconvenient fix is to change my Home URL to the Site URL, save the file, login (The site is messed up at this point), and then change the code back on my FTP while remaining logged into wordpress on another tab. Unfortunately this site is for a client, and they will not be satisfied with these extra steps just to get into the website.

Any and all help is appreciated!