The name of Alipay account is different from the mobile phone bound to Alipay account. Check whether the Alipay account name bound by Taobao is the original mobile phone number.

Login to Taobao Account > My Taobao > Settings > Alipay Binding Settings > The mobile phone number or email displayed on the page is the name of the bound Alipay account.

If the name of Alipay account is the original mobile phone number and the new mobile phone number is not registered with Alipay account, then use the new mobile phone number to register on Alipay website. After the new Alipay account is activated, unbind the Alipay account on the Taobao binding page and then bind the new Alipay account.

If you can't solve it, you can contact the online cloud customer service website for detailed consultation.