**Answering for completion due to rough previous answers**
This can be caused by a bad WiFi chip, software issues or a setting issue.
In most cases (especially with a modern AC/AX router) it’s a network security issue - especially modern routers which typically use WPA3 out of the box. The WLAN chip Sony used here isn’t WPA3 compatible. This issue leaves you with a choice:
- Bad option (please, please avoid if possible): Powerline Ethernet. The reason I despise this option is unless you *need* to reach for these things, there’s better options. Powerline is only as good as the wiring in your house and is honestly the network equivalent to the Konami code. If your home’s wiring is hopeless beyond supplying power, so is Powerline. I get it - going into your attic or basement ain’t fun, but a good Cat6a wall run from the office to your PS3 won’t be crap.
- Basic (reduced security): Downgrade to WPA2-AES systemwide (PSK is less secure, so AES>PSK when possible!).
NOTE: Expect your ISP to give you a hard time under the guise of “security” if it’s one of those web managed specials like the modern Spectrum router) and you can’t change it - they may lie, so know your router so you can push back, and do not be afraid to cite credentials like if you hold an A+ cert as a weapon against their reps. WP3 isn’t a big of a bump from WPA2-AES in regard to security, so it is an option - just a subpar one.
- Intermediate (secondary compromised, but main secured): Secondary router with WPA2-AES (Again, PSK discouraged but so be it if all else fails) as an option/default on the same network.
- Advanced (requires enterprise or business class gear from eBay, FB Marketplace or your preferred source of surplus): Setup a VLAN with your main network on VLAN 1 and the legacy network on VLAN 2 to quarantine the risky LAN on the network. SOME prosumer routers do it, but you usually need a Cisco, HPE, Aruba or Juniper switch for example and two routers. Your best bet is an old 802.11n/ac router that can run DD-WRT. This is the fastest way, since you don’t need to tell your ISP off. If you can manage these things, this is the way to do it even though you basically have a “home lab”.
If it’s not the network, start with resetting the PS3 back to factory settings, and pray. You may even need to format the PS3, so backup the console first. If it doesn’t fix that way, the WiFi chip is bad.