Directory name conflict?

[grimson]

https://imgur.com/a/WteTSdk

Hello,
I do have 3 USB disks connected to a Synology NAS.
Unfortunately, I cannot add multiple USB disks to MinimWatch as it conflicts somehow.
Please see image

OK
/volume1/Music
/volumeUSB2/usbshare

I cannot add this folder:
/volumeUSB3/usbshare
'Directory name conflict; correct highlighted value and retry'

Where is the conflict? is it the 'usbshare' in conflict? I cannot change this unfortunately.

Thanks!