New AC 2200 mesh extender problems

[Nixy]

I have set up my mesh extender fine but it seems to have triggered WiFi problems and we now have interruptions to WiFi that we didn't have before. Also the smart connect function is off and won't activate. When I turn it on it comes up with a configuration error? 
not sure if this is a problem but any ideas?

[plemans]

What actual extender do you have? AC2200 is a speed

What firmware is on it? 

What router is it connected to? 

What method of setup did you use? WPS or the installation assistant?

[Nixy]

I have an EX7700 extender. It is connected to a virgin media router and I set it up using the installation assistant. Not sure about firmware but I haven't changed anything from buying it. 
I am having to switch it off now as it's causing more issues with devices not connecting to the WiFi and losing connection. Very frustrating as it's causing more issues than it's solving. 

[plemans]

what virgin media router is it? 

Firmware is key as there was a sketchy version for the EX7700. 

If you log into the extender, it should be on the status page