@nebulon I agree
I believed that many users will have smooth installation
I downloaded ubuntu server 20.4.03 ISO from their website, create vm under esxi 6.7 and i use pfsense as my router and firewall in my home, and i don't know if my firewall setting is non-standard
next week i will put production server in my local server hosting provider and make a fresh ubuntu/cloudron installation from there and hopefully the installation will working without any trouble like this thread
anyway, i appreciate all cloudron's staff helping me with this issue