When registering on AliExpress, if the system prompts that the email address already exists, it usually means that the email address you provided has been used by another AliExpress account or Alibaba Group account (such as Taobao, Alipay, etc.). In order to ensure the uniqueness and security of the account, AliExpress does not allow the same email address to be used by multiple accounts.

If you really want to use this email address to register on AliExpress, you can try the following solutions:

Check whether you have already used this email address to register on AliExpress or other Alibaba Group accounts. If so, you can directly use this account to log in to AliExpress without re-registering.

If you forget the registered account information, you can try to retrieve the account through the "Forgot Password" function of AliExpress or Alibaba Group. Usually, you need to provide some personal information or verification method to verify your identity, then reset your password and log in.

If the email address is replaced from another account, you may need to wait for data synchronization to complete before you can use it again for registration. Generally, data synchronization takes 2-3 hours, and can be completed within 24 hours at most. You can try to register with the email address again later.

In addition, to avoid similar problems, it is recommended that you carefully check the email address when registering to ensure that there are no input errors. At the same time, for the security of your account, it is recommended to change your password regularly and avoid using a password that is too simple.