301 redirect to new domain

Hi
I move my website to new host and use a new domain name, and the old domain also point to new host.
I add this in .htaccess

# BEGIN WordPress
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.oldsite.com
RewriteRule (.*) http://www.newsite.com/$1 [R=301,L]
# END WordPress

It’s not work so well, http://www.oldsite.com did redirect to http://www.newsite.com, but http://www.oldsite.com/* sitll http://www.oldsite.com/* with right page.

I think maybe the code should be

# BEGIN WordPress
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www.oldsite.com RewriteRule (.*)
http://www.newsite.com/$1 [R=301,L]
# END WordPress

But it would be a 500 internal server error.
Last time I got this error was enable Wordfence’s Falcon Engine and solved by add these codes in .htaccess from their docs.
And change file access to 404 for solved this issue.
Did those affect the 301 could not work fine?