Cannot install Crater invoice - Help please

Hi Guys, I am trying to install Crater (invocing app). On step-4 of the installation process it gives error and cannot proceed further. The error I get is ‘Domain verification failed’. So far I have tried to run installation in incognito mode and also double checked all folder permissions, also tried to install from another pc. But I keep getting this error.

here is the screenshot.
I would really appreciate some help.

I have CentOS, PHP 8, mariadb and lightspeed web server.