ReadyNAS on a Mac (VPN DIsconnected)

We have multiple users struggling to connect to our Ready Cloud NAS via the desktop application. 

All Windows 10 pro users are having no issues, all Mac users are receiving a 'online (VPN disconnected) error message. They are able to access the web UI with no problems.

I have tried to update to the most recent version of the software (version 1.19 on a Windows but only 1.17 on a Mac??). I have disabled and reactivated the Ready Cloud service from the Admin UI to no success. 

I have also updated my OS system from High Sierra --> Mojave --> Catalina but still no luck. 

I can see a lot of people having the same problem over the last couple of years but no clear solid solution. 

Can anyone help?