Glad to know I'm not the only one. Moving from Windows to Chrome OS I needed a new password manager, and wanted one that was local (not cloud). Found Enpass and all looked good, got the trial version installed on the Chromebook, synced with old Windows machine, seemed like it was going to be a good choice and was ready to pay for it when I discovered the ethernet issue. Just like lammoth, I can get it to work just fine on WiFi, but as soon as I switch to ethernet the chrome extension quits working, telling me that I need to enable autofill.
On mine at least, when I enable autofill with wifi on, it's looking for 100.115.92.2, port 10295. But with ethernet it's looking for port 10395. I've tried entering the ip address with both ports, but neither works.
And to add to the confusion, if I have just wifi connected and turn on autofill, it's fine. Plug in the ethernet cable with wifi still on, and it quits working. Unplug the cable and it starts working again. It's a shame about this. I really thought this was going to be an alternative to Roboform