Some Win10 PCs will not connect to SMB share, others will

I have a network SMB share (provided by a Netgear ReadyNas Firmware 6.9.3)

Of the 15 Windows 10 Pro PCs I have tried to connect to this share, about half can't "see" the share, while the other half can see and browse to it with no trouble.

Those that can't see it get this: "Windows cannot access [sharename]" 0x80004005 "Unspecified Error"

I am trying to connect anonymously (this is a general share, only accessible in my LAN and I don't want to use accounts).

All of the PCs are in the same LAN segment, with the NAS (10.168.200.x.

All of these PCs (working and non working) were formerly domain joined to an SBS 2008 server, but have been removed from that domain months ago. The troublesome PCs show that they are NOT a member of a domain.

I have also completely disabled the PCs firewall for testing purposes, with no effect. There are no other firewalls between the devices and no firewall on the NAS.

The PCs can ping the NAS device. Google suggests many people experience this issue, but I haven't found anything that works.

Any suggestions?

I was able to get the troublesome PCs to connect by creating a user on the NAS device and using those credentials to connect.

It did not work unless I manually input the user account into windows credential manager as devicename\account; just putting 'account' produced a 'the credentials did not work' style message.

When I did not first manually add the credentials to credential manager, and attempted to browse the shares on the NAS device, windows reported that it could not find the device/share (which is an entirely inaccurate error message - as mentioned in my question, name resolution and ping was working).

I was not able to get the PCs to connect anonymously.

This is not ideal but it's not a perfect world and this issue has already sapped stupid amounts of troubleshooting time.

Thank-you all for your assistance.