If by 5G network you're talking about the cell phone standard, then no Roku supports that. If you're speaking of 5GHz Wi-Fi, then none of your Express devices support that. That's why the model number is so important when asking for help. Different models have different capabilities and the name isn't good enough - it's the model number that matters. Some ISPs appear to be turning off 2.4GHz APs on their routers, so that's a possibility of why none of your Express devices are seeing your Wi-Fi.
Model 3810x sN 213052753912
I'm needing the IP address for my ruku before I can do anything so I connect remote on my phone to t.v
If you have 5 Express models, you should know and understand that the Express has never supported 5 GHz. They have always been a single band device. And Roku isn't alone with devices that don't support 5 GHz. If that was a requirement for you, then you needed the Ultra or the Stick. Those are the only Roku devices that support 5 GHz.
If your Roku is connected to the network, it has an IP address and you should be able to find it with a network scanner. There are numerous freeware programs that can scan your network and report back the devices found.
If it's not connected to the network, then it doesn't have an IP address and you can't connect with the app.
I had this issue with my roku express. It has been happening since I bought it a month ago. On Sunday I discovered that my ISP Vodafone had changed the channel my WiFi operates on to 12. When I manually changed the channel to 11 ( a bit of a faff because Vodafone has disabled this function in their latest app update so had to find an old version) the Roku saw my WiFi network. Not sure why my Roku can't see channel 12 but I haven't had a problem with connectivity since I changed the channel to 11.
Thank you this worked to fix mine 🙂
Roku devices will only use WiFi channels that are usable in any location. Channels 12-14 are not usable in some parts of the world, so Roku cannot see them. This is by design. Same thing with the 5 GHz radio, where the DFS channels are invisible to Roku devices. 5 GHz only uses channels 32-48 and 149-165.
Same problem. seems like a common thread.