Hi
@OscarYao, Welcome to the community and thanks for posting. Sometimes it does have to do with browser we recommend you use Google Chrome or Internet Explorer. You can also try to delete cache and cookies. If you experience the same situation with a different browser, I would suggest to reach out to our customer service for phone assistance. Kindly click on the words " Help / Contact " at the bottom of the PayPal page and use the phone option in the blue band at the top or very bottom of page dependent on what country you are in. Scroll down past the list of help questions and click on 'Call us' bottom of that page. Log in and get the code. I hope this helps. If this post or any other was helpful, please enrich the community by giving Kudos or accepting it as a Solution. Stay safe.
