Sporatically Lose Connection to Shared Folder

I own an insurance agency and so I've created a folder with a bunch of commonly used files on a computer in my office that is running Windows 10 Pro - 64 bit. The folder is located in the administrative user's account and I have the folder shared via: Share > Specific People > Everyone (Read/Write) > OK.

Every computer runs on the same network via an Ethernet cable that runs from my modem, to my router, to my switchboard, to the respective computers. Very rarely we will need to connect to the WiFi so that we can print on a color printer.

As far my sharing options, I have the network setup as Private. The Private profile under Advanced Sharing Settings I have the following settings for every computer in the office:

• Turn on network discovery
• Turn on file and printer sharing

I give you all of this information because I am incredibly frustrated with what is happening. I never know if I can actually access the shared folder from one of the other computers that it is not hosted on. Sometimes I can access it with no problems, other times it will give me the following error:

Windows cannot access ...\Public Check the spelling of the name. Otherwise, there might be a problem with your network. To try to identify and resolve network problems, click Diagnose.

Obviously the Diagnose tool doesn't find anything, otherwise I wouldn't be here; the actual error code is 0x80070035.

Am I doing something wrong? This very frustrating and to be honest, it is impeding with my business at this point.