I think, but it's only a quess..
Your router/switch doesn't provide the Raspi with dhcp IP adres, so the device doesn't receive IP adres. Hence, you cannot go to browser API
Normally Raspi boots under dhcp, static IP adres config isn't necessary (normally I have to say)
Check your connection/utp cable and see if LAN Raspi port gets green/orange lights blinking
Make sure router/switch puts out dhcp, or turn on dhcp server option 🤔