Sharing - Password needed? But that's turned off!

Force Gaia · October 21, 2019

I hope this is a simple issue for someone to just point me at the right setting, but i'm having issues getting sharing working between PCs on my network. The issue is if any clients try and connect to my server, they're prompted for a username and password despite password-protected sharing being off, and even if i put in the server's username and password, won't allow the clients to connect.

The Server (called "Ravnica") runs Win 10 Home 1903, is a desktop tower connected via Ethernet.
The Client (called "Innistrad") runs Win 10 Home 1809, is a laptop and can be connected by either Wireless or Ethernet depending on location
The secondary Client (called "Ixalan") runs Win 10 Home 1903, is a desktop tower connected via Ethernet.

The issue is if either Innistrad or Ixalan try and connect to Ravnica, they're prompted for a username and password, which is both undesirable (as Ixalan is my housemate's PC) and even if Ravnica's admin username and password are put in, it'll not allow access. This is despite all PCs having all of the following set:

Private network
Network discovery on
File and printer sharing on
Password-protected sharing off
128-bit encryption
Public folder sharing on
Same Workgroup (called "Multiverse")

All the folders (and printer) i need to share on Ravnica are shared, with Read permissions for "Everyone", with the Microsoft-account-linked user as an admin (which is the only named user on Ravnica)

Why are the clients being prompted for a password in this situation?

Extra data that may help, but i doubt it's relevant

The network is as follows:

{ISP wireless AP/switch/router} <-> {gigabit switch A} <-> {Powerline Adpator} ~~

~~ {Powerline Adpator} <-> {gigabit switch B} <-> {Ravnica}

~~ {Powerline Adpator} <-> {Ixalan}

{Innistrad} is either connected by wireless to {ISP wireless AP/switch/router}, or by a wire to {gigabit switch A}
There are a variety of other non-PC devices attached to all three switches, including the TV, games consoles, a raspberry Pi, etc, but none are configured to use the network share.