1, has sent a message frequency limits, if properly before you can send e-mail. Suddenly transmission fails, the most likely exceed the transmission frequency
2, if the message is sent using the client fails please send the same message can be sent if the test is successful, if also sent unsuccessful, and accounts related to the mail server may be what has been done on this account restrictions
3, using just registered near Netease cloud mailbox to send pictures / (text + picture) will fail, this is normal. Registered replaced by longer Netease cloud account can be sent successfully
4, when sending mail message size as not more than 3M, because the mailbox has sent a daily volume limit, when the transmission volume exceeds a certain value (such as qq-mail is 200M), it can not send mail large amounts of memory, the more memory only allowed to send small mail, send large messages can fail. So please try to send the message size is smaller than 3M
5, if the same account and transmits the received E-mail Account failure in a machine, on the other machine may send a success. It is likely that the machine IP letter too, is disabled
6. If you need to locate a problem, please inform the sending account, failure to receive the account information, and send content databases (GW_EMAIL_MT table) recorded