Hello,
Enable debug mode in WordPress – https://wordpress.org/support/article/debugging-in-wordpress/ to find out what error appears on your site, it will point you in the right direction what needs to be fixed.
Please provide FTP access, then I will ask one of our developers to check the problem more deeply and help you.
If you do not know how to create FTP contact with your hosting provider, they will help you.
Regards