Why is my desktop's IP not consistently accessible from my iPhone on the same LAN?
I just got Fiber 1000 installed yesterday, and the gateway (router) is ARRIS BGW210-700.
I'm a software engineer and have run my own local server on my desktop, whose IP is: 192.168.1.[redacted]
When I try to browse to that IP (or to http://mycomputername.local) from my iPhone, it doesn't work. Similarly, when I try to use the Network Tools iOS app and ping that IP, it just says "Timeout".
Then, if I temporarily disable the Windows 10 Firewall (which I've never had to do in all the years I've coded websites), pinging the IP from the Network Tools iOS app suddenly works.
And pinging `mycomputername.local` also then works (and resolves to the correct IP).
Then, what's really interesting is that I can re-enable Windows Firewall and then continue browsing (using Chrome on my iPhone) various pages such as http://mycomputername.local/page1 and http://mycomputername.local/page2 even when the Firewall is active.
But then eventually http://mycomputername.local fails to load (and pinging the IP times out again too).
It's as if my desktop is only ever visible on the LAN for a short lifespan before becoming invisible, and then I need to temporarily disable Windows Firewall again to revive it.
What is going on??
What settings on my router or Windows PC can I change to enable other devices on my LAN to browse to it consistently?