Older v2 hub was offline (unplugged) for a long time, now it won't do much of anything!

Start by following the troubleshooting guide in the following thread. That thread also applies to V2 hubs in some instances. https://community.smartthings.com/t/troubleshooting-smartthings-hub-2018-and-aeotec-hub/298332

tagging @nayelyz @Itati