@MichaelSTL I don't know what pass-through mode is in ATT router but the general considerations should be: If your ISP router is in bridge (modem only) mode the Deco should be in router mode. In this...

@vbPhil In the thread I posted the OP is using RE220 ethernet port in RE mode for connecting a wired device. Did you try another ethernet cable as I suggested ? If nothing helps contact your retailer...

@vbPhil A way to be sure that RE ethernet port is working properly is to switch the RE in AP mode and test the behaviour. Change the ethernet cable that you're using - use the cable from the RE kit...

@jlock02 If you've meant the RE - it doesn't have a WAN port, it has only LAN port. If you've meant your router - the RE can't change your main router settings - it's just a repeater. This must be...

@Tex1301 Try this guide for configuring the EAPs.

@jlock02 Enable ping from WAN temporarily is possible only for wireless modems/routers. REs should not block any ping requests/responses on their ethernet port.