EX3700 - Android and IOS Devices Not Connecting

I have been able to connect the EX3700 to the router (in extender mode) and, in turn, connect a Windows 10 laptop to the EX3700. Internet connectivity is fully funcional via this route.

However, when I subsequently try to connect x2 Android phones and x1 iPhone, none of these devices is able to complete a connection to the EX3700. The Android phones just sit at the status of "Obtaining IP address", before the connection attempt eventually times out. The IOS device reports "No Internet Connection", despite the fact that the EX3700 is, at the same time, extending that Internet connection correctly to the Windows device.

I have undertaken a factory reset on the EX3700 but this has had no influence on the problem.

The firmware version applied is: V1.0.0.72_1.0.47.

Can you advise what may be causing this and how it can be overcome?

Thanks.