The problem about use AWS s3 to builing a landingpage, who can explain it?

[siwujin]

Hello ,
I set up everything on the AWS s3,
when I open the website url without "index.html" added,will show the Error below (like this: https://www.*****.com/lp1/)
<Error><Code>NoSuchKey</Code><Message>The specified key does not exist.</Message><Key>lp1/</Key><RequestId>D8ACB148FDC35E81</RequestId><HostId>baPTGrwqhdNjvo8OQPvVpoH9N4ZNEEzQy8RzH03Jb93rHZxZUvpBZQNsoav5SDBl0ENHgs2saDg=</HostId></Error>

But when i open the site url with "index.html",It was ok. (like this: https://www.*****.com/lp1/index.html)