I am setting up backup software on my proxmox server (Zerobyte) that I want to backup certain data from Unraid server. I need to setup a volume on my proxmox that can access the Unraid share. I have setup a few SMB shares as Private before on my Unraid which I can access just fine from my Windows machines using the user id and password. Zerobytes is running in a container. In Proxmox under DataCenter > Storage I can add the SMB Share and access it in the command line just not in any container running on proxmox. I am guessing it is something simple I am missing because I see video's of this exact setup online and it works easy for them (of course). I should mention I am not a very familiar linux user. Any help is greatly appreciated.

Try the Unassigned Devices Plugin and mount the Proxmox share on your Unraid server. If Proxmox has rsync installed on it, use rsync to transfer the data between the servers. (rsync will to either push or pull files between computers. You just have to remember to get straight in your mind which is the source computer and which is the destination computer for the files you want to transfer.)