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I have a website that runs wordpress.

I’m new to this so I was messing with the settings to see what they do.

My domain name was www.example.com and there was a setting that was allowing me to change it.

This is the link it led me to https://codex.wordpress.org/Giving_WordPress_Its_Own_Directory

After changing it to www.example1.com I no longer have access to my admin page.

www.example.com works but it lost all the CSS elements, when I try to add the wp-login at the end it redirects me to www.example1.com and prompts me with that error.

Does anyone know how to fix that or revert these changes? I only have access to the server, not the host, so I cannot reinstall wordpress for this domain.

It keeps redirecting me to www.example1.com, how can I stop that?

Those settings are stored in the wp_options table in the database.

If you can access the database with PHPMyAdmin
Location the wp_options table and find the records with the option_name of home and siteurl and change it back to the correct url.

Your host may also be willing to help with this.