Omada ER605 OpenVPN "Server Poll timeout" etc.
TL/DR: Connecting to ER605 OpenVPN server from/through LAN side is NOT supported, nor does the device help you through this snag.
In an effort to save others from the time and struggle...
It's 2025. I bought this in 2023 with the expectation to configure an OpenVPN server on my home network. I wanted to access my home network remotely for two reasons: #1 remote administration of devices only accessible from my internal LAN, and separately, #2 to tunnel and proxy my Internet traffic back to my home network when i was away.
The ER605 was advertised as having OpenVPN server capability, so I purchased it. However in 2023 the firmware that was available did not allow for me to do everything I wanted. I honestly can't remember what was missing, I just remember being disappointed. You can review the firmware availability dates on tp-link.com to see when they release the new major firmware versions.
So earlier this week, I revisit my project to enable the advertised features of my ER605, find the new firmware, bootstrap to a middle firmware version, because updating from where I was to the latest was not even possible, then finally end up with V2.1.1. This firmware version seems to allow for me to configure an OpenVPN server to do what I want. So I configure the server as directed in the guide from my LAN, because I'm not out here on the Internet configuring my gateway router from a WAN port. And when I go to test the VPN tunnel on my same laptop I get "Server poll timeout" from my OpenVPN client. I dig around in the ER605 looking for any helpful logs. There are literally zero helpful logs. Only evidence of the DHCP server chugging along and fact-of my initial web console login on the LAN port.
I eventually come across this community thread (https://community.tp-link.com/en/business/forum/topic/665990) "ER707-M2 - Local LAN client cannot connect to OpenVPN on the routerER707-M2 - Local LAN client cannot connect to OpenVPN on the router".
In short, tp-link has configured the ER605 such that the simple use-case of connecting to your VPN server from the inside (originating from LAN) out (continuing through WAN, then back in), is not supported and instead enabling it, OR (more egregiously) providing any breadcrumb clues about whats happening in a log (god forbid) they're just ignoring the activity. So I, go into my network settings and disable all other adapters, and tether my laptop to my cell phone, and try again. Voila. it works. . .