Kodi seems to require you to set the level. The current minimum setting on 19.1 and 20 is none. The maximum was set to v3
In the Settings -> services -> SMB Client box, set both min and max to v1 if using window clients.
Haven't tried it with Readynas SMB protocol shares.
May need to clear memory on Android system / phone for KODI.
settings -> apps -> memory -> cache -> memory.
clearing memory will erase all configuration, and permissions and all shares will need to be re-entered.