Google cloud bucket use for static services without having a domain, needs index.html explicitly in URL

[Sam M]

Hello!

I have a bucket (e.g.  My-bocket) and I could reach it via

 https://My-bucket.storage.googleapis.com/ as an example. The bucket does not have domain name but I intend to use it as static content for web. In side the bucket there is index.html and the bucket has Legacy Storage Object Reader and it had index.html as the mian and also as an error 404 page. 

The problem is that I must write  https://My-bucket.storage.googleapis.com/index.html in order to see my page rather than  https://My-bucket.storage.googleapis.com/ 

Could it be the main and redirect 404 only works when the bucket has a domain name?

In addition to it, when I use https://www.My-bucket.storage.googleapis.com/ I get "Your connection is not private" inside Chrome. What is the reason for that and how could I fix it without making a new bucket . Thanks!