Ip issue

Right I have a bit of a problem I am trying to manage my router and a mmdvm hotspot when I put the ip address in the top search bar or go on manage my router in wifi settings it come up saying either it does not exist or has moved to another address. If I get another phone (samsung) it works ok I have tried in flight mode turned data off to use only WiFi updated my phone reset WiFi and Bluetooth settings made sure no vpn is active in have used Samsung Internet and chrome any suggestions thanks