That must be because when device unistalled you have disabled secure rejoint mode on the hub.
How you uninstall devices from IDE or app?
Once you have uninstalled all the devices that use the unknown repeater ???, turn off the hub for about 10 minutes, if it is a v2 hub, remove the battery too.
When you connect it, check that you do not have the unknown device??? on your network before adding devices again.
Hopefully you get lucky and it fixes it.
Did you check the wifi channel of the router and the zigbee channel of the hub?
Here is a @nathancu post with link to explaining this