Can access NAS via web interface but not Windows explorer

[efny]

I have a Synology NAS behind my pfsense. I set up an OpenVPN server. I can access the server and can subsequently access the NAS via it's LAN IP in a web browser at https://mynaslanip.com:portnumber, but I cannot access the share at \mynaslanip.
The windows network is set as private, sharing and discovery are enabled.
I have routing set up to the subnet and the NAS IP directly.

I would appreciate any thoughts.