Weird one, DS120J can see on one laptop, but not on other?

[pjgtech]

Had my DS120J since Dec 2020, worked fine. But today cannot see it on one laptop?
All my laptops are win10 and have access to the shared NAS drive.
I have BT Broadband and smart hub.
The NAS drive is connected via ethernet to a Netgear 8 port GB switch, which in turn is connected to the BT smart hub.
On one of my laptops today, I could see the nas drive with no issues.
On my other laptop however, I could not.
I can't see it via file explorer, I can't see it using Synology Assistant. I get an error, see attached.
I have tried testing network cable, its fine. I have changed network ports, no difference. I have tried resetting BT hub, resetting NAS, restarting laptop, etc.
Nothing seems to work, this laptop simply cannot see the nas drive, but yesterday it could, as far as I know, nothing has changed at all since yesterday, so its very confusing?
Anyone have any ideas? (NB: I also pinged via command module 8.8.8.8 and it worked fine).
Thanx, getting frustrated now, I bet its something really simple!
Edit, I also turned off Windoze firewall, just in case, still no joy...

 

[EAZ1964]

Try. :

Cannot map network drive due to "System error 86"

I apologize if this is a stupid/frequent question but I couldn't find this exact issue on the forums or honestly anywhere; maybe I just don't know what to look up. I setup my DS920+, made user accounts, created shared folders, applied privileges, etc. For example, let's say I created the user...

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