I purchased a new E4 yesterday 02 May 24 and trying to join with an existing Deco network comprising two Deco M5s (one connected to incoming router). The E4 will not get beyond the blue pulsing light after many minutes. I have rebooted all devices and have reset the E4 via the Reset under the device and have upgraded the firmware on the M5s. I have also moved the E4 close to the main M5. Both M5s continue to work fine. Any ideas please?