Connection time out when trying to connect to my gitlab installation

So I recently installed gitlab on a fresh EC2 instance running Amazon Linux V2 using the following instructions.

I have set up the right security groups which have opened SSH, HTTP and HTTPS to my office IP address and the external URL as

external_url ‘http://gitlab.rockar.com/

but when I try to connect to the host it I receive the ERR_CONNECTION_TIMED_OUT error.

running a NC command on port 80 on the server hosting gitlabs comes back as successful. I was wondering if anyone could provide some guidance please. Thanks.