eufyCam can’t connect to HomeBase in Ethernet mode

I purchased a 4 camera eufycam set, and 3 of the 4 cameras connect to my HomeBase fine in Ethernet mode, but one just refuses. It still makes the high-pitched “dialling” and the successful connection “charm” sounds, but the voice prompt just says “failed to connect”.

I’ve tried resetting both the HomeBase and the eufycam (by pressing the sync button 5x), to no avail. Battery and wifi signal are both around 100%.

The only way I’ve been able to get it to connect is by changing the HomeBase to wifi mode.

This same camera has now also been randomly going “offline” every couple of weeks, and the only to re-add it is to change the HomeBase back to wifi mode and repeat the whole process.

What do you think is wrong here?