Unable to Reach Application on localhost for Tests Run on Safari 8 and 9, and Edge

You may have noticed an issue when using Sauce Connect Proxy with not being able to connect to your web applications at localhost when using certain ports. For example:

1. Spin up a local server serving content on port 9998.
2. Start Sauce Connect Proxy.
3. Open a Sauce Session in Safari 8 or 9, or Edge, and try to load localhost:9998.
   You won't be able to access the content.
4. Start another local server on port 3000.
5. Open localhost:3000 in the same session
   You will be able to access the content. 

This will happen with Safari 8 and 9, and Edge browsers. The issue is these browsers will never send localhost URLs via a proxy, and always use a non-proxied connection to reach localhost. 

You have two options for a workaround. 

1. Modify the hosts file in the machine running Sauce Connect Proxy. Just add a fake domain, such as myname.local, that points to 127.0.0.1. Then, point your tests to that URL instead of localhost. This will skip the localhost proxy entirely and prevent the issue, and may even improve the performance of your tests. 
    
2. Use the Sauce Connect localhost proxy to connect over a different port. The answer to the question "Can I Access Applications on localhost" in the Sauce Connect Proxy FAQs contains a list of all the ports you can use with Safari.