I'm attempting to use either Showoff.io or localtunnel on my Macbook Air, to make a Rails app running on a Vagrant VM available for testing on external devices. Other uses with identical hardware on the same network are able to do this successfully using the same Showoff credentials.
I am not running a firewall, and my Macbook is more or less set to factory defaults. I've tried this on two different Internet connections, one wired and one wireless. The symptoms are the same for my paid Showoff.io account, a free 5-minute showoff.io account, and a free localtunnel account. I'm completely out of ideas on what I could possibly try next to diagnose this problem.
Can anybody suggest a possible next step for figuring out why I'm experiencing this delay or how I could fix it?