**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 house wiring. It’s the Konami code of networking because if you’re dealing with vintage 20+ year old Romex, it’s gonna fail hard. I get it - going into your attic or basement isn’t fun, but a good Cat6a wall run (with Cat6 on the other end) from the office to your PS3 won’t be crap. Cat7 is expensive for home use.
- Basic (reduced security): Systemwide WPA2-AES downgrade (PSK is less secure, so AES>PSK when possible!).
NOTE: Expect your ISP to give you a hard time under the guise of “security” (especially if it’s one of those app managed specials like the modern Spectrum router) and you can’t change it - they may lie, so push back as needed with confidence. Do not be afraid to cite credentials like an A+ cert against the ISP. The thing is WPA3 isn’t a big of a bump from WPA2-AES in regard to security, so a full system downgrade 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. These will coexist and one acts like a repeater (the router must be using ASUSWRT for this, or support DD-WRT; stock FW rarely works in “repeater mode”.)
- Advanced (requires enterprise or business class gear from eBay, FB Marketplace or your preferred source of enterprise surplus): Setup 2 VLANs: VLAN 1 (main), and VLAN 2 (quarantined). NOTE: SOME prosumer routers support this, but you usually need a “managed” switch (Cisco, HPE, Aruba, Juniper or L2/L2+ TP-Link) or a capable “Smart Web” like the lower end managed TP-Link ones (DE, PE or MPE). For the quarantined network, your best bet is an old 802.11ac router that can run DD-WRT with WPA2-AES selected, or ASUSWRT. This is the fastest way, since you don’t need to tell your ISP off, and your main network isn’t compromised. You’re basically building a “homelab”, but if you can hold your own go for it. The equipment is CHEAP.
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.