Trouble sharing Macs on same network

[tuqqer]

Filliam H. Muffman wrote:
Are they all on the same frequency network? Have you tried restarting everything in sequence?

Thanks, Filliam. Double-checked and they're all on the same wifi connection.

And we shut down all the units and then started them up again.

I'm next going to try deleting the User accounts again, from all devices. I also suspect that it could be some cache of the stored password/name of the user accounts.