WiFi issues upstairs

[JSM90]

Hi,

I'm currently experiencing issues with my WiFi upstairs.

All connections downstairs are absolutely fine, however, those upstairs are requiring the router password again and then suggesting that it's incorrect (despite 100% being as stated on the router).

I've done the broadband test on the Sky app but it's indicating no issues.

Could someone suggest how to resolve this problem, please?

[jamesn123]

@JSM90 
This would suggest you have some sort of booster or 3rd party extender messing it up. Is there anything you have that could be causing it?