On my vero4k, I can not add a source. I specified an ip address and that resulted the same. I searched the forums and did not get a match for the error I am seeing - path not found or invalid.
I’ve tried with wifi and ethernet, thinking it was a connection issue.
Well could be a smb version issue.
I think easiest is to use fstab based samba mount as explained in the wiki. Alternatively try to change maximum protocol under settings → Services → SMB Client
Well, my fault for using SMB when I have UPnP setup on my NAS servers. When I went back and looked at the options, I finally saw it. I was so focused on SMB.