1. Choose united states in manual installation.
2. PHP REQUIREMENT: check in "Requirements check" of install and https://osclass-classifieds.com/download and https://docs.osclass-classifieds.com/minimum-requirements-i3
3. Take dump on login page.
4. On mysql 5.6 the script was throwing error "Specified key was too long" hence kept minimum mysql as 5.7 since 8..3.0