How do I mount a Synology remote folder on Android 8.0?

My phone is not rooted. I have shared folders on a Synology drive which I can mount on a couple of different Macs running different versions of Mac OSX. I am assuming the folders are published using CIFS/SMB but I cannot mount them on my Android phone using file manager type applications. So far I have tried "ES File Explorer", "Network Browser" and "File Commander" none of which are able to connect. I can connect to the Synology home page using a browser on the phone so network connectivity is OK. Do I need to disable/enable firewall/sharing settings on the phone?