Broadcast DNS name visible to PC but not phone

I have a Raspberry Pi which my PC can reach at http://raspberrypi.local.

My Android phone (which is on the same WiFi network and has mobile data switched off) gets DNS_PROBE_FINISHED_NXDOMAN.

Why can my PC but not my phone reach the Pi?

The problem is explained in the post How to get mDNS working for Chrome on Android?

Android doesn't have any support for Bonjour (aka mDNS, aka zeroconf networking) in standard name resolution.

Unless the Android app you're using explicitly uses an mDNS library, it will not see raspberrypi.local.

You'll need to discover your Raspberry Pi's IP address (192.168.xxx.xxx) and use that.