This is not uncommon when using a VPN. It's because many other users are all connecting from the same VPN server. Since the website only sees the IP address on the VPN server you are connecting from, it sees an abnormal amount of traffic coming from the same IP address. That verification measure is in place to ensure that you are a legitimate human trying to search, not a robot. For example, without that measure in place, someone could create a new search engine. But rather than collecting website data themselves, they could just pass your search through Google and use Google's results on their own website. Obviously, this is a big simplification, since many websites will collect more data than just your IP address to determine whether your visit is legitimate or not, which could be part of the reason that you don't have issues when using Google Chrome. The easiest way around this is to change what server you are connected to within NordVPN. Hope this helps.