Two stations seem to have died on me. Is there something I can try?

So the outdoor module, and one of the inndoor modules were no longer on my device list in the app. I put in new batteries in both of them, but they did not re-appear. So I then tried to do the install new device configuration. But no contact with any new devices, and no green light in the units when I put in the new batteries. 
Any steps I should try next before throwing them out?