EDIT: The pi is running this from the output of hostnamectl:
Operating System: Raspbian GNU/Linux 9 (stretch)
Kernel: Linux 4.19.66+
I have been running Owncloud on a pi zero W with a static ip for a few months with no problems. Recently while getting support from my ISP, the tech support reverted some settings including the SSID and password of the 2.4 GHz wifi on my modem router. I don't know what else was reset in the router and the issue wasn't the router, just bad wireless drivers on my laptop. I went into my pi and updated the wifi information, and it connects fine at first.
A while after connecting to the router, the pi becomes unreachable on the local network by other devices, but it can connect to the internet and ping other devices on the network. Also if I use a tool built into my router to ping the pi it does not work. My desktop and laptop have Owncloud client software to keep some files in sync. The Owncloud client software reports "No connection to (my shared folder name) at (my url). Connection timed out." This happens both on my local network with my desktop and laptop, and on my laptop when I am away from my home network.
Things that will "wake up" the pi and cause the desktop clients to see it again:
-Logging in to the pi's web interface
-Pinging another device on the network from the pi
-Restarting the wlan0 interface with "sudo ifconfig wlan0 down" then "sudo ifconfig wlan0 up"
Note that the web interface is always available, the pi becomes undiscoverable at random times, and the first two of the above solutions do not always work. Also the client software cannot access
I had this problem months ago when I first got the system running, but I cannot remember what I did to fix it. I have researched the pi zero w wifi power saving mode. I disabled power management for wlan0 so that iwconfig reports "Power Management:off" among other output. I also added "iwconfig wlan0 power off" to /etc/rc.local before the "exit 0" at the bottom of the file to turn off power management every reboot.
I would like help figuring out how to keep my pi zero w from becoming undiscoverable on my network.