Connect Device to Mac localhost Server?

Have your server listen on 0.0.0.0 instead of localhost.

I had the same problem. I turned off my WI-FI on my Mac and then turned it on again, which solved the problem. Click Settings > Turn WI-FI Off.

I tested it by going to Safari on my iPhone and entering my host name or IP address. For example: http://<name>.local or http://10.0.1.5