Make sure that both URLs are exactly the same.
If you do not have access to the admin area of your WordPress site, then you can change these URLs using FTP. There are two ways to do that using FTP:
Update WordPress URL and Site URL Settings in wp-config.php File
Once connected to your website using an FTP client, locate wp-config.php file. Now you need to edit this file in a text editor like Notepad.
Go to the line that says
/* That's all, stop editing! Happy blogging. */, and just before it, add this code:
Don’t forget to replace example.com with your own domain name. Now save your changes and upload the file back to your server.