The sole calls node in Rockingham County has been offline for a few days:
View attachment 175943
If/when that node comes back online, you should see the missing agencies re-appear. There is no other VIPER calls node close enough to receive traffic for Rockingham County.
The reason you can still see fire dispatch listed is due to the fact that Rockingham Fire Dispatch is being provided by a conventional-only (not VIPER) node in neighboring Caswell County (
Node 4013: Caswell County (Conventional) (Caswell County) - Live). The provider of that node has included the Rockingham County Fire UHF simulcast frequency in addition to the Caswell County frequencies.