ES File Explorer Pro returning "server not found" when accessing a SMB share on Ubuntu

With a Windows machine, I can connect with IP, user, and password to some Linux shares. With ES File Explorer Pro, I get strange "server not found" messages. This is what I do: 1. Open ES File Explorer Pro 2. Search the LAN (the machine is listed) 3. Access the machine (I notice it's getting all the shares listed) 4. Entering a folder gives a permission error. So I add the folder to ES File Explorer server bookmarks and try to access it again, but I get a "server not found" error. 5. Then I edit the bookmark (and notice it's logging as an anonymous user) so I set the domain with the machine name, server adding smb://ip/share/ to the address, user, and password. And still, I get "server not found". All the other machines, some Linux and some Windows are accessing Just fine. Except for the Android devices with ES File Explorer Pro. What am I missing?