Debian not starting the apache service

Hello,

i have this error:
LISTEN 0 128 0.0.0.0:80 0.0.0.0:* users:(("lighttpd",pid=1327,fd=4))
LISTEN 0 128 [::]:80 [::]:* users:(("lighttpd",pid=1327,fd=5))

I changed the listen ports to 8081 in: /etc/apache2/ports.conf

And changed all the websites VirtualHost to 8081 in: /etc/apache2/sites-enabled/000-default.conf

But when i write the link in the browser it gives me: 403 - Forbidden

Any Help please?