The red indicator on your eero may be caused by the way you locate it. In order to obtain good signal coverage, eero should be placed where there are no obstacles. If the red light is still on, you can disconnect eero from the network and reconnect it to the network. If the problem persists, try restarting the eero network. Check out the article here

Thanks for this. I had completely deleted my network and restarted, but the problem persisted on that same one eero. I have since swapped it out with another of the eero devices, and all are now running well. I guess the one that previously had the red light issues has just a little less signal power than the others - It was bought as a single add-on unit to my original 3-pack.