Help configuring SMB/External storage

Hello everyone,
I’ve tried googling around for the errors and I’m not having much luck.
First, I need to connect my Nextcloud VM to my file server over SMB.

Host -
Share - Images
Global credentials - username password
(no domain, no subfolders)
Error! - Server provided an empty response.
Red square, I sometimes get a yellow trapezoid-y square, but this system is not verbose enough to decode what is going on.

File Server: Server 2012 R2 permissions allow with the provided local account credentials
Tried the Mac File share over SMB, same error with a folder shared in the same way as Windows.

Second, since I can’t connect to SMB, how do I tell the Nextcloud VM that it has an 80gb drive?
It keeps erroring out with low free space like it still has a 20GB drive.

Either case, I need help troubleshooting this issue pronto if I’m to start syncing terabytes of images for friends.