Hello ero1893,
Thank you for reaching out to Apple Support Communities.
Do you know if you previously limited your iCloud Web access using an iOS or macOS device:
"How to manage web access to your iCloud data
You can manage iCloud.com web access in iCloud settings (requires iOS 16.2, iPadOS 16.2, or macOS 13.1).
On iPhone or iPad
- Open the Settings app.
- Tap your name, then tap iCloud.
- Tap to turn off or turn on Access iCloud Data on the Web.
On Mac
- Choose Apple menu > System Settings.
- Click your name, then click iCloud.
- Click to turn off or turn on Access iCloud Data on the Web.
When you turn off Access iCloud Data on the Web and then sign in to iCloud.com, you see an alert confirming that iCloud Data Web Access is Off and you can’t access your data. To turn web access back on, you can also select the “Manage access on device” link that appears on iCloud.com and follow the prompts on one of your trusted devices."
Additional details can be found here: Manage web access to your iCloud data
If the issue persists, can you provide a few more details? What browsers have you tested with? Also, can you test with other browsers?
Cheers!