when using the mail () method of php mailer, if you send the mail, but why the status of the http request is "canceled"?

I am using the php mailer library to send emails, in my project it is working well, send the emails that I indicated, but my question is why the status of the request is "canceled"? Besides that, when I see the detail of the request, it tells me that "Provisional headers are shown". So I find it curious that even if the process is done well, the status of the request is "Canceled".