Check the basics
Use the same sign-in method and email address you used to create the account. Check for typing errors and finish any verification requested by the sign-in flow. Never send a password, one-time code or recovery code to support.
Try a clean connection
Reload the page, check your connection and use an up-to-date browser. If a browser extension blocks the sign-in flow, test with the extension temporarily disabled. Do not clear site data until you have saved any unsaved work.
If the problem continues
Record the exact error, approximate time and time zone, browser and the page you were opening. Use the help contact options. If you cannot sign in, public articles remain available and the website support assistant can provide general guidance; account-specific ticket creation may require verification.