Let’s start this one from the back…
When it comes to remote access, there’s multiple players involved – some are under your control, others aren’t. Your ISP can e.g. start blocking certain traffic/ports or switch their network to a mode where you’re no longer able to access your home server from outside your home network.
Sadly, there’s no one-size-fits-all solution. You’ll have to get your hands a bit dirty when trying to troubleshoot this.
As for configuring the router… it appears the device configuration highly depends on using their app…
- Eero: How do I configure port forwarding
- Eero: What advanced features does Eero support → Static IP address setup
If things keep failing, I recommend taking a look at the remote access troubleshooting to pin down what’s going wrong. The individual findings/output from the troubleshooting will be required to provide additional assistance / guidance.
