First, please try refreshing your email application (e.g. Yahoo! Mail) or click the "resend" button to see if you receive the email.

If you still do not receive the email, you may have opened the Expo ID site in your email application (e.g. Yahoo! Mail), so please close the “Authentication by email” screen and check the email address you registered for your Expo ID.
After confirming your six-digit one-time password, click on the link for the ticket site in the same email.

For details on the settings for starting up with a recommended browser, please refer to section "2.3 Setting Up a Supported Browsers" in the Expo ID Registration Manual below.
Expo ID registration manual:
https://www.expo2025.or.jp/wp/wp-content/themes/expo2025orjp_2022/assets/pdf/tickets-index/id_registration_manual_en.pdf 

Paper tickets/ticket vouchers are also available.
Paper ticket/ticket exchange ticket website:
https://www.expo2025.or.jp/en/tickets-index/voucher/