In trying to reconnect an S4R extension which was persistently dropping off the wi-fi I tried pressing the 'Reset' button - it now flashes blue when powered up. I'm trying to re-attach it to the system, which has one S4R hard wired to the router and another extender S4 - the disconnected unit was the 3rd of the 3-unit array. No luck with the interenet - there's nothing out there about re-attaching the reset S4R that I can find. Any help appreciated.