EX7300 extender connecting but no internet: 'DNS server isn't responding' or 'IP address not found'

[sam3js]

Extender had worked for a long time but stopped working two weeks ago.

Performed a factory reset multiple times and went through the set-up assistant, including one attempt with an ethernet cable linking the router and extender.

Devices connect to the router itself no problem, and when I've tried a different extender that also works. Occassionally my phone briefly connects to the EX7300, but no other devices can use it.

Troubleshooting the wifi either tells me the DNS server isn't responding or the IP address does not exist.

It did seem to stop working at roughly the same time my family attempted to set up some new extenders. That may just be a coincidence, even after disconnecting the extra extenders the EX7300 hasn't worked since.

I would really appreciate any suggestions or guidance you can offer.

[plemans]

1. what router are you connecting to? not all routers play nice especially if the ISP supplied devices. and it might have worked fine and the isp updated their device. unknown without knowing which you're connecting to

2. What firmware are you running on the extender?

3. you said you tried redoing the install using the installation assistant? 

4. have you tried re-installing the firmware on it? if it got corrupted, a reset only removes settings. you'd need to re-install the firmware to overwrite any bad firmware. 

If you're needing multiple extenders, I'd look at moving to an actual mesh system like netgear orbi. Extenders don't play that nicely with each other for multiple reasons. 

1. by the very nature they loose 50% of their bandwidth for each hop. Reason why is they have to recieve and retransmit the signal. and they can't do both at once. So if you go router----extender-----extender, that 2nd extender is going to be running at less than 25% of the speed of the router. 

2. if you use the same ssid as the router with the extenders, they can end up connected to each other instead of back to the router. If you're using mutliples, its best to setup unique ssid's for them.

[sam3js]

Thanks so much for your detailed advice, the router is a BT Smart Hub.

The firmware was just the standard which the extender comes with I believe. I've looked into reinstalling the firmware and the only guidance I found was to update the firmware. I tried updating it but unfortunately the same issue is still there.

I did find some guidance on how to reinstall firmware for the router itself. But admittedly even if it was applicable, messing around with IP is probably beyond my tech capabilities.

Thanks for your advice on multiple extenders, I'd already told my parents this which is why we removed the other extenders. One is usually fine for our house.

I'll probably give up on the extender to be honest, I've already reset it loads of times and tried some advice I've seen online. We do have another extender which isn't quite as good but does the job. Really appreciate your reply and advice nonetheless. 

[plemans]

there's multiple bt smart hubs.

They also sell their own line of extenders.

One thing I've found with bt smart hubs is you need to disable smart setup on the bt smarthub. it can cause signal intercepts and cause drops because it can redirect devices to BT web page's offerings. Its not really a "smart setup" for BT hub. 

And the EX7300 is a pretty rock solid extender. I've used on prior and it worked pretty great. 

To reload the firmware on the extender, start by downloading the firmware from here:https://www.netgear.com/support/product/EX7300.aspx

make sure to select your correct version from the drop down box. 

Once downloaded, extract the file. (right click in windows, extract all)

just log into it through the browser  then go to settings-->firmware update----->browser.  And select the file you downloaded and extracted.

This will reinstall the firmware. 

Once fully reinstall, I'd start over by factory resetting, and reinstalling it. Again, just make sure to disable smart setup on the bt hub.