iCloud
iCloud sign-in panel on my PC has been running non-stop every 2 minutes for 8 days. It rejects my CORRECT ID/pwd. The software is up-to-date and I've changed passwords on my PC, iPad and iPhone.
iPad Pro, 12.9-inch, 6th Gen, Wi-Fi
Maybe a solution here? --> What to do after you change your Apple ID or password - Apple Support
If you still have questions or problems:
Refer to this document for ways to contact Apple --> Choose your country or region - Official Apple Support
Select your country (also look for "other" regions), then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.
or:
Contact Apple for support and service by telephone --> Contact Apple for support and service - Apple Support