@SunRaz 

I've done it on occasion, but programs I use use the Network.

There could be a PERMISSIONS problem though.

Using the Windows Credential Manager I have this one for my router:

User name is the name I signed into on my PC. Not 100% sure this is required, but my older router I had did protect the drive, it is not protected now on my Archer A20.

Next make sure NET VIEW can see the router:

So as you can see, I did a NET USE to Y: for my USB connected drive.

One question, does your enclosure show it as 2 drives or one?

I'll also assume your old router worked fine, but did it have the same IP Address?

I'll assume all devices are on the same workgroup?

Can you connect to the other devices or see them in Windows Explorer if they are able to be seen?

@SunRaz 

I didn't mention in my post but I do see the USB share in Windows Explorer too.

If you Google for "view nas connected to a router in Windows Explorer" you'll find a lot of hits for this problem. Maybe one of those will help?

You didn't mention the NAS make and model though? It could be its OS getting in the way, but I'd not suspect that?

I have attempted to access the USB drive via mapping and Network Neighborhood and get the same results. I don't have the exact wording for that error message, but it mentions something about the domain. Nevertheless, I have suspended all attempts at resolving this for now, as I need to move on with some important work that I need to complete. For now, I have the USB drives connected to my desktop, allowing for mapping and access over the LAN by all devices. As I recall from previously reading router specs is that there are limitations on the amount of storage capacity that can be used, so perhaps I have exceeded the that capacity. My total USB storage capacity is 4 TB, so maybe that is where the issue rest.

SunRaz wrote

I have attempted to access the USB drive via mapping and Network Neighborhood and get the same results. I don't have the exact wording for that error message, but it mentions something about the domain.

@SunRaz 

I recall something like that?

I had a router that worked fine, and I did NOT use the DEFAULT W10 Domain name of "Workgroup". Had to change it back to make it work. Suspect your PC and the NAS have different domain names.

I'd assume NET VIEW would have shown the NAS though? The do a what I posted to view the contents? You wouldn't see it if it was on a Different DOMAIN.

I have a 4TB USB External drive connected to my router, I'd assume the SAME FILESYSTEM is used on all routers, so the size shouldn't be a problem. I assume the NAS is self-powered, not using the USB port for power. Some 'portable' USB drives use the USB port for power and those can have problems.

If you Google the exact error you got, it might help you out figuring why?

@IrvSp

I have not changed the workgroup name, so it is still at the default name.  If I had, it would had required me me change the workgroup name on all my devices inorder to map my laotptops and the desktop.  Since all my devices drives are successfully mapped in all the devices, I am sure that it is not a domain or workgroup naming issue.  As I have previously indicated, doing this for years, this has never been an issue previously.