I have a sony X7500F 2019 model ,so whenever I connect it to my Router it shows internet is not available for some wierd reason , it happens mostly when I start the TV ,I have to restart the router and TV multiple times and pray that it works .
All my other devices work perfectly fine with the router , sometimes it'll show not signed in to the network when I already have .
Do you have modem/router or a modem and router?
Possible IP assignment issue maybe set a static IP address. Or Wifi Band issues with 2.4ghz or 5ghz which would explain why it works some times. All in theory. You can disable one band. Or Login to your router and see what options are available to you. Usually there are logs from the devices that connect to the router might have more information on the device and why it's being flagged/blocked. Or Perform a factory reset on the tv, I'd start with this.
Source: decades of using janky electronics experience./ Hack0r
Any make sense. Let me know what