16.4.1(a) Unable to Verify Security Response

@sberman has researched the issue. Apparently it is because the update is intended to be installed automatically, with a staggered rollout. So if you manually try to install it you may get that message. This is from AppleInsider:

While the update is seemingly available to download straight away, you won't necessarily be able to install it. [Analysis] reveal that there is a "granular ramping logic," in that it will allow a percentage of users to install

the update at a time.

———snip-------

Only 5% of users will be able to install the update in the first 6 hours of release, rising to 15% by 12 hours, 40% by 24 hours after release, and 70% by hour 36. After 48 hours, all users who downloaded the update will be able

to install it.

———snip-----

Attempts to install the update before the device is allowed to will display a notice saying the iPhone is “Unable to Verify Security Response" and claiming it is because the device is "no longer connected to the internet." Despite the apparent lack of internet according to the message, users can still go online normally with their iPhone without restriction, and the notice only applies to the update.

No VPN.

It worked after 1 hour when I retied

Yes that is message I got. I Turned phone off and wait like 15 minutes and tried again and it updated

Are you using VPN in your connection?

I got in by retrying a 3 rd time deleted update and all is okay now

With this sudden rash of activation issues it may be a problem on Apple’s end. There is nothing listed in Apple - Support - System Status, but this frequently lags behind the actual status, so check it periodically.

Thanks for this, Apple giving us the option to manually install the update just after it’s been downloaded with no message in the pop up to let us know it will fail if you try to install it in the first 5 hours is confusing.

‘Security Responses & System Files’ updates should all done in the background with no input from the user required.

Same here and took about 3 minutes to install then reboot. All is good. Just need patience.

Same here, on both an iPhone and an iPod. The rest of the message is "failed verification because you are no longer connected to the internet." However, this isn't true - I'm typing this message on a Macbook Pro that IS connected to the internet, and both the iPhone and iPod can browse and send/receive email without issues.

14 pro max and 12 pro max both getting problem regardless of whether connected to Wi-Fi, cellular, or vpn on or off. Also reset network settings to no avail. Have plenty of space, plugged in, 100% battery.

Apple’s problem.

Same problem on my iPhone 11, tried resetting the device and cycling the Internet connections, same issue

It may be a server or activation issue but you should wait for Apple to fix the issue. There is no issues in your end and you should try the update in the next five minutes.

fix - Apple Rapid Security Response 16.4.1 Download Hits iPhone, iPad, Mac [Update] • iPhone in Canada Blog

cswartout wrote:

I was able to update finally. BUT, it was a little disconcerting as the phone immediately shut off and restarted once the update started.

Updates always require restarting the phone.