Try power cycling the router. There are some router hacks that are only temporary & disappear once the router has been power cycled. Make sure to wait at least five minutes for the router to finish booting. During that time see if the "----off" SSID disappears. If it does, then it was likely your router.
If the "----off" SSID disappears during the router reboot & reappears once the router is ready, then you should probably perform a hardware reset of the router to factory defaults. How you do this can vary by routers, but many times there is a hidden recessed button you must hold down. Check your router's documentation. Resetting to factory defaults should change the WiFi SSD to the factory default (no idea what that would be...password is likely on the bottom or back of the router as is the router's admin password).
You also want to make sure your router's firmware is up to date.
You will need to check your router's documentation on how to access the router's admin portal. Most router's admin portals are accessed using one of the following URL's in a browser (if it is a really old device, then you may need to remove the "s" from "https" & make it "http" instead, hopefully your router is current):
https://192.168.1.1
https://192.168.100.1
https://10.0.0.1