Totally agree, I should have added something as simple as a version check and not rely on the user to review the minimum requirements. It will be a priority to add it for the next version.
You can try in this test installation that has the same requirements that you tell me and you will see that it installs perfectly.
(WordPress 4.9.8 and PHP 5.6.37)
Website: https://gleaming-unicorn.w6.poopy.life
Administration Panel: https://gleaming-unicorn.w6.poopy.life/wp-admin
User: demo
Password: 2zkRv6UFBo24
This facility will be available for 24 hours.
I guess the bug is caused by some kind of incompatibility with some theme or plugin you use on your site.
The only way to check it would be directly on your site. If you want me to do it, I would need access data to the administration panel and also to the FTP of the site (this way I will be able to uninstall it manually in case of failure). You can send them to me at [email protected].
I appreciate your revaluation ??