You can try powering it off for several minutes to see if that resolves the issue. Remove the batteries if you have a v2 hub.
RBoy
(www.rboyapps.com - Making SmartThings Easy!)
3
Try what @jkp said. Also check your connectivity (ethernet cable or wifi), solid blue typically means cannot connect to the internet/ST servers. It may help to try connecting the hub to a different internet connection if you have access to it (like a neighbor or office).
I have the same problem. It went offline on Sept 28th whilst I was on vacation. Now I am home I’ve followed JKP’s advice and rebooted several times, replaced the batteries in my v.2 and tried resetting to no avail. It seems locked in the static blue light mode. I cannot connect to the hub in any way online although there is no problem with my internet and the hub still controls some of my lights on the presettings automatically through sensors but not on timers!
I will try putting a ticket in with support. I’ll let you know what they come back with.