I have 3 Pi Zero W on my local network, serving as audio devices with a web interface (running volumio).
Sometimes (only sometimes) I am unable to access them from my android phone (neither via host name, nor IP address), while still being able to access all other devices on the network, including a Raspberry Pi 3B that is connected via cable.
If this was not strange enough, my iPhone is able to access the websites. Something between Android and the Raspberry's is not working, as it is the only affected combination.
If I try to traceroute or ping from the Android phone, it just times out. Ten minutes later, everything is miraculously working again.
Any ideas on how to analyze this problem?