E500 stop broadcasting ssid.

Recently our client reported to us that an E500 cnpilot series access point stopped to broadcasting ssid. The configuration is unchanged and also this device seems to operate normally in the cloud platform . We have tried to force a reboot and a firmware reflash without a success.. Any suggestion will be helpful

When you say the configuration is unchanged, how did you verify?  Directly on the device, exporting the device config in cnMaestro, observing that the device is Synced in cnMaestro?