I’ve been working on setting up CSS Visual Regression Tests on wordpress.com lately, and I was having a hard time getting OSX and IOS tests working with the Sauce Labs Connect Tunnel. I discovered that only specific ports will work. It’s not super well documented, but I found that both port 3000 and 4000 work. So I changed my local server to serve on port 4000 as in http://localhost:4000 and now my OSX and IOS tests connect over the Sauce Labs Connect Tunnel!
I thought I’d share this because it was incredibly hard to find and there’s no official documentation on it, and even the Sauce Labs support team couldn’t figure it out after I spent hours giving them super detailed log files multiple times.
I hope this helps you! :-)