mail.proton.me是一个无需手机号就可以注册的免费邮箱，但是注册之后想要用于注册其他的平台的账号之前，需要先给这个邮箱设置一个恢复邮箱，不然会自动屏蔽掉注册验证码的邮件，导致无法用此邮箱注册其他平台账号。请注意官方邮件的提醒，如下所示。

Dear User,

Thank you for your interest in our service.


Our system has flagged third-party service registration emails shortly after your account creation, which goes against the intended use of our service and may indicate disposable account usage.

We've implemented these measures to enhance the overall reputation of Proton Mail. This helps protect our domain and prevents the risk of our IP being banned by third-party services, which could affect service availability for all users.

Currently, your account has some limitations, restricting its use for registering on third-party services.

To remove these limitations, you will need to add a verified recovery email address or phone number, or consider upgrading your account.

Learn more about how to verify your account recovery methods here: https://proton.me/support/set-account-recovery-methods.

Thank you for your understanding and cooperation.

Best regards,

The Proton Anti-Abuse Team