A.
If you have already registered your Expo ID, go to the login page via the link below and click on "Forgot ExpoD?", which will take you to the "Confirm your ExpoID" screen, enter your first name, last name and other information and click the red "Send email" button, which will send an email containing your Expo ID to the email address registered to your Expo ID. You will then receive an email with your Expo ID at the email address registered for your Expo ID, allowing you to confirm your Expo ID.
If you have not yet registered your Expo ID, please register for one.
Expo ID login screen:
https://usrmng.accounts.expo2025.or.jp/idmng/users/screen/menuScreen