I am working on 2 servers and .htaccess file working on 1 server but not working on second server.

.htaccess file

RewriteEngine On
RewriteRule ^socket.io/(.*)$ ws://example.com:3000/socket.io/?$1  [P,QSA,L]

I am working on socket, so i dont want to show :port in url, so i just redirect url to port within htaccess

Url examples server 1,

ws://example.com/socket.io/etc Redirect ON ws://example.com:3000/socket.io/etc (working)

http://example.com/socket.io/etc Redirect ON ws://example.com:3000/socket.io/etc (working)

But on server 2, same code on different domain return "Internal Server Error"

I dont want to change my code, because it is my backup server, so i want to run same code, but what i am missing? Is there any apache extension required or what i am missing?