You might be lucky and solve it by inspiration. When that fails, fall back on a careful, thorough and systematic approach as explained here.
Network Utility
Among the most useful are Archive Utility, now including Apple Archive compression, and Storage Management. But Network Utility is now non-functional.
Using Lookup, Ping, and Traceroute to work out why you can’t connect to a website. Is your ISP blocking it, perhaps?
Sierra sticks with the old favourites like Disk Utility, but still can’t repair permissions or keychains. A new app, Storage Management, has been added.
How can I investigate frequent errors when browsing of “Can’t find the server”?
Hidden deep in domain names are the lyrics to a Joss Whedon song, from an Internet musical.
I sat in front of my iMac, only to discover that the Internet was gone. The right lights still shone on my modem-router, but no matter where I pointed Safari, I got a near-instant error.
Like all sophisticated systems, Macs do sometimes go wrong. Indeed in some hands they always seem to be […]
The Eclectic Light Company 