What Enitech said.
If your old hub is still around, you could try “excluding” each device from it first, then “including” to the new hub.
If your old hub is not still around, or not working at all, then you need to do a factory reset on the devices. Then include them.
In zwave, each device stores the network ID of the primary hub that is allowed to sent it commands. Since the new hub has a new network ID, the old devices are ignoring it, as they are supposed to. They know they “belong” to the old hub.
So you either have to have the old hub release them through the exclusion process, or reset each device to “no primary yet” and then let the new hub include them.
If you didn’t have to do this, then anyone could drive by with a working zwave hub and hijack your devices. So it’s just a security feature of zwave itself, nothing to do with SmartThings.