iPhone SE on iOS 18.5 won’t connect to home Wi-Fi but other devices work fine

Re: “… This is a problem created by Apple and Apple needs to fix it …”

A statement apparently based on anecdotal observation.

For comparison, our own family’s iOS 18.5 SE3 is working fine in a moderately “dense” WiFi environment.

Have you tried resetting your “Network Settings” ???

Warning, this Reset will also erase saved SSID passwords so “be prepared” before making that “leap.”

As you have confirmed, the problem is not with your phone as you are able to connect to other networks just fine. The problem is simply a matter of science and the limitations of the 2.4Ghz band that is quickly becoming deprecated with the amount of devices that are now using WiFi. That band is susceptible to interference from other radio transmissions and your phone (and any other phone) contains a Cellular, Bluetooth and Wifi antenna that overwhelms that band when congested with other devices. You can read more about those 2.4Ghz networks here and how common the problem you are experiencing is that is not unique to your iPhone:

https://www.iotforall.com/2-4-vs-5ghz-the-science-behind-connectivity-issues-in-iot-devices

Steve Roth wrote:

Thanks again, Mac Jim.

>your phone...contains a...antenna that overwhelms that band

I don't understand what the antenna "overwhelming that band" means here. It's already "overwhelmed" with other networks' interference. Does the iphone antenna also "overwhem" it? All my other devices including a heavily used mac have antennas as well, which don't (noticeable?) "overwhelm" that band.

Are you suggesting there's a hardware (antenna) issue with the iphone that doesn't exist on other devices's antennas?

Your linked article explains, "Interference reduces wireless signal quality." But if there's no noticeable connectivity or performance issues from that, who cares? I don't. If I run into those kind of issues, I'll troubleshoot them.

The alternative, I think: this is just a problem created by some Apple programmer who thought it best to lock users out of a network if there might be connectivity or performance issues. Nothing else seems to make sense given the facts on the ground here. ??

If this was as you suggest (your comment bolded) a problem created by some Apple programmer, wouldn't this affect every iPhone SE on iOS 185? This forum would be flooded with complaints if it was, yet it's not. And Apple didn't selectively make this issue happen to you alone. Do you have an issue? Yes, without question. While wanting to blame Apple is the easiest option, it's not the logical one. Apple isn't responsible for every router out there. I suspect you do have an issue with the 2.4gHz band. It's also possible you use a VPN on your iPhone and I don't think anyone has asked yet if you do. VPN's are not only not needed on an iPhone, but they without question cause connectivity issues and should be removed.

If you're having an issue with the router, that isn't something within Apple's control. Is your router dual band? Have you set up a 5gHz and 2.4gHz Wifi access point, so you can choose the one which you can connect to without interference from the other band?

I used to have all sorts of issues with the cheapo routers most internet service providers give. So, I finally moved to a modem from my ISP and installed a Mesh Network in my home. Not only do I have more stable Wifi connectivity, I can reach places in my home and outside my home, I could never do using the router from my ISP.

Again, blame Apple if you want, but it's not going to solve this for you.

I suspect you are using a 2.4Ghz WiFi network and what you are experiencing would be common with that band that has multiple devices connected to it. Sorry, I would not be able to help further without dealing with your router to use a 5Ghz band instead. The 2.4Ghz band is susceptible to interference with multiple devices due to channel overlap and bandwidth. The multiple antennas on your iPhone is creating just enough additional interference where it will not connect.

Your other devices have 1 antenna, or possibly 2 if they also use Bluetooth, where any phone is going to contain 3, which will be more problematic on a network that is already subject to the interference. You have troubleshooted by testing if your phone works on other networks and it does, so the confirms that the issue is with your current network. I don't see any benefit why Apple programmers would think it is best to lock users out of a network, so from a logical point of view that makes no sense.

We have no idea what router you have and you have made it clear you do not want to mess with it, so from that stand point there is no solution. What would need to be done is to create a 2.4Ghz network for older devices that do not support 5Ghz, then create a 5Ghz band for all your other devices to connect to. How you do that will depend on your router and will solve the problem if you are exclusively using the 2.4Ghz band. The problem is not with any device manufacturer and the same thing happens with Android phones if using the 2.4Ghz band on an already congested network.

We've said pretty much what we can say to you on this. You didn't answer any of my questions, so I'll just depart and hope you solve this. Keep in mind this is a user to user only forum. We've taken our personal time to try to offer what insights we can. What you do with them is up to you.

Re: “… Understand: I've been

troubleshooting Apple device issues since 1985. Not a newbie or know-nothing here …”

Yes, your CV was included in your original post; nor has anyone here impugned either your creds or experiences.

Best of luck.