SMTPMailer: Did not receive expected 250 (2)

Hi ,dear the PKP boys and girls, after I clicked the tag of forget password and input the correct email,I didn’t get any email,and the PHP error log is:SMTPMailer: Did not receive expected 250 (2) bx157
The same thing happened in /User Home/manage/prepared email,but the mail function works everywhere else,I used ojs2.4.8.3

Is this same question already is discussion here?

I’m sorry that I think it might be now, I may need to switch to another server.