Troubleshoot - Configuring Synology, OpenVPN & iPhone

Hi all, I am trying to set up OpenVPN on my Synology and iPhone so I can watch all my personal media with an app called Infuse. I’ve read a ton of blogs and watched a bunch of videos but for some reason, I can’t seem to get it working. I was hoping anyone here might be able to tell me what I’m missing.

Hardware

  • Synology DS216 play, version 7.1.1

  • Genexis Platinum-7840 router (provided by ISP, no passthrough)

  • Asus AC86-U (wired directly to my ISP’s router)

  • Asus AC68-U (Set up as Mesh network, Synology is connected by cable to this router)

I’m aware that this creates a double NAT which means I need to port forward twice. I think this is also where I’m struggling to fix the problem.

What I’ve done so far

  • Installed the OpenVPN app on Synology
  • Configured OpenVPN on Synology (Port, UDP Allow clients, TLS Auth key)
  • Checked OpenVPN Privileges
  • Added exceptions to Synology firewall
  • Configured static IP address for Synology
  • Configured DDNS
  • Exported OpenVPN config file, updated YOUR_SERVER_IP PORT
  • Watched The Complete Guide to Port Forwarding
  • Watched Setup Synology OpenVPN Server

Conclusion

While configuring DDNS I can choose to set the IP4 Address to auto or to LAN. Auto is a completely different IP address than LAN. Which one should I choose?

I feel like I’ve tried every combination possible, but I can’t seem to figure it out. Any help would be greatly appreciated

How should I configure my routers?

Thank you,

James