One Solution: There Was a Problem Connecting to the Server error

Lots of people have been seeing their network shares connectivity break after updating or upgrading their macOS operating systems. I, too, lost my ability to connect to my local PC by simply clicking on its name under the Shared heading in Finder's sidebar -- or to even connect using SMB in macOS's Connect to Server dialog -- at some point recently, after updating from Sierra to High Sierra on my Mac mini.

I suddenly started receiving the dread "There was a problem connecting to..." error that tons of users seem to have been experiencing:

After spending several days searching the internet, reading dozens of posts related to the problem, I could not find a single suggestion that fixed the problem -- until I happened to see a screenshot posted in Google Images of a Mac's Network Settings page that made a lightbulb go off. I fixed my problem in 60 seconds and can now connect to all my local shares again, just by clicking on the share's name in Finder (as well as using the Connect to Server dialog):

Make sure the domain "local" is included in the DNS/Search Domains settings for your network connection. That's all there was to it, in my case:

After I added "local" to my Search Domains, the problem went away immediately.

If you're not familiar with changing Network settings in your Mac's System Preferences, there are plenty of guides posted on the internet. Just Google "network settings mac".