Safari redirect to 404 after loading

You may try some of these steps, please check after each step...

1. Sometimes, a simple restart can resolve temporary software glitches. Turn off your iPhone, wait for a few seconds, and then turn it back on.
   1. Restart the device. That's it.
   2. Still not solved --> Force restart iPhone - Apple Support
2. Do you have any extensions installed in Safari? Certain extensions, especially ad blockers or content filters, can interfere with page loading and cause redirects. Try temporarily disabling your extensions to see if the issue persists.
3. Sometimes, cached data stored by Safari can interfere with proper page loading. Try clearing your browsing history, website data, and cookies completely. Make sure to back up any saved data before clearing!
4. Ensure that the date and time settings on your iPhone are correct. Incorrect date and time settings can cause issues with website security certificates. Go to Settings > General > Date & Time and make sure the settings are accurate.
5. Check your "Content Filters" and "Restrictions" settings in Screen Time or General settings. Ensure these are not accidentally causing websites to redirect.
6. While less likely, connectivity problems can sometimes lead to unexpected redirects. Try connecting to a different Wi-Fi network or using cellular data to see if the issue persists.
7. If the issue persists, you can try resetting all settings on your iPhone. This will not erase your data but will reset all personalized settings to their default values. Go to Settings > General > Transfer & Reset > Reset > Reset All Settings and confirm the action. Note that you will need to reconfigure your settings afterward. All settings—including network settings, the keyboard dictionary, the Home screen layout, location settings, privacy settings, and Apple Pay cards—are removed or reset to their defaults. No data or media are deleted.
   1. Reset All Settings: Return iPhone settings to their defaults - Apple Support:- Return iPhone settings to their defaults
   2. You can return settings to their defaults without erasing your content.
   3. If you want to save your settings, back up your iPhone before returning them to their defaults. For example, if you’re trying to solve a problem but returning settings to their defaults doesn’t help, you might want to restore your previous settings from a backup.
   4. 
8. Make sure you have the latest updates installed.
   1. Update Over-the-Air (OTA) —> Update your iPhone or iPad - Apple Support (IN)
   2. Update using iTunes/Finder —> Update your iPhone, iPad, or iPod touch - Apple Support (IN)

If none of the above steps resolve the issue, it is recommended to reach out to Apple Support or visit an authorized service center for further assistance. They can provide specific guidance based on your device model and iOS version.

You may get better and prompt responses if you may kindly provide the iPhone Model that you have and the iOS version if it is known to you and re-post.

With the limited information that you have provided, It is hard to even guess the problems faced by you. 

You may get faster and better responses to your query by --> Writing an effective Apple Support Commun… - Apple ...

Please re-post with detail so that someone else can help.

Try this page:

https://discussions.apple.com/undefined

it keeps refreshing every 30 secs as evidenced by a progress bar appearing at the bottom every 30 seconds. This is an example I’m having in this very forum when using Safari on iPhone XR latest iOS 17.3.1. This is an example of discussions dot apple dot com redirecting to an /undefined page.

Here’s an example right now for me.

iPhone - Apple Community

that page in Safari. I stare at it and in 15 or 30 seconds it redirects all by itself with zero input except for my face looking at the screen to the undefined page above.

Something broken here.

It’s only affecting Safari. I’m writing you from Chrome. I had to copy the Safari page address before it refreshed and redirected, then pasted into Chrome for stability.

this seems very prevalent on pages where input is required like Help Chat or completing a web form.

I've been experiencing this in Safari for a few months. I thought it was an iPhone problem or a data problem but just recently figured out it’s only Safari causing me this grief.