I am investigating a connectivity issue reported by a user running latest iOS 26.4 Public Beta on an iPhone 17 Pro Max. Unfortunately, I am unable to reproduce this behavior on my end as I do not have access to an iPhone 17 Pro Max for testing, and my current devices do not exhibit the issue. However, the user's logs suggest a system-level networking issue :
Symptoms:
- Flutter App (package dio): Requests fail with The connection errored: Failed host lookup: 'mydomain.com'
- Firebase SDK: Unable to fetch Firestore documents
- Duration: The outage is random, lasting between 5 to 15 minutes before self-resolving
- Scope: It affects both Wi-Fi and Cellular data
By the way I found this report from another developer experiencing the exact same behavior:
"I run a mobile app that has millions of users. As of 1-2 weeks ago, we started getting reports that the app isn't working (failing to connect). It then goes back to connecting anywhere between 5 to 15-20 mins later. Every single one of those users was running iOS 26.4 beta, and their phones ranged from iPhone 17 PRO Max to regular iPhone 17s, to iPhone 16 PROs and Maxs. The only other thing is that all these users also had Apple Private Relay enabled. During the time the app wasn't able to connect, other apps on their phones like YouTube, also failed to connect. The issue is persistent whether on Wifi or cellular, didn't matter. I upgraded my iPhone 16 PRO Max to iOS 26.4, and wasn't experiencing the issue. I enabled Private Relay - and a few mins later on my own phone, I couldnt connect on my own app, and YouTube/Gmail also were experincing issue. It self-resolved 5-10 mins later. But it kept happening throughout the day. I've tested Network reset, I've also re-installed the apps, both still continued to have those weird intermittent outages. I just updated the phone to the latest version that was released a day ago, so far I'm not experiencing it, but as you can imagine, this is such a weird behaviour that it's concerning for me that I can't figure out the exact way to replicate it."
I asked the user to test with iCloud Private Relay disabled, and it immediately fixed the problem -> so maybe this suggests that it might be related to how Private Relay handles traffic or DNS resolution in this beta ?
Are other developers seeing an increase in SocketException or host lookup failures on the 26.4 Beta? Is this a known regression related to Private Relay that is expected to be patched before the RC/Final release?
I’ve not heard of widespread problems with iCloud Private Relay on the iOS 26.4 betas, but that doesn’t mean that this problem isn’t real. My general advice on this front is that you file a bug. Or, in this case, encourage your user to file a bug. They can do that using Feedback Assistant. Ideally they’d do that immediately on seeing the problem, so that the sysdiagnose log attached by Feedback Assistant captures the issue in progress.
If they do this, ask them to pass the bug number along and then post it here.
Share and Enjoy
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Quinn “The Eskimo!” @ Developer Technical Support @ Apple
let myEmail = "eskimo" + "1" + "@" + "apple.com"