Please recommend some free or opensource Status Page.

What is a status page?
below is some examples

https://www.cloudflarestatus.com/https://www.redditstatus.com/

It literally says if your website is up or down to your visitors or if some of services are down....

It's an old topic, but customized status pages are crucial for SaaS and e-commerce sites. Surprisingly, it hardly gets any attention here. You can find tools to build your own status pages here. There are at least 10-20 different options on the market right now.