iPhone won’t connect to vpn

I just bought 2 year plan of Nord . So started installing it on my devices . Alle went good , until I tried it on my iPhone 15 pro . Installed it , logged in al good Then when pressing connect to vpn . Getting the message , trying to find the fastest server.. and it loads and loads.. then get the message , trying to connect , will not take longer than a minute . But you guessed it , no connection . It actually tanked my whole cellular internet connection .
Had to reboot the phone .

Is there a extra setting I need to input , isn’t it just login and go . Or is it only available through WiFi and making vpn on my phone useless ?