我在 Stack Overflow 上问了这个问题，有人建议我来这里。我通常不亲自处理这类问题。
我在 SQL Server 2008 中运行一项计划作业，但是在发送电子邮件时遇到问题。
我收到错误信息；
The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 1 (2013-04-11T10:05:12). Exception Message: Cannot send mails to mail server. (The operation has timed out.). Sending Mail using Account 1 (2013-04-11T10:06:53). Exception Message: Cannot send mails to mail server. (Failure sending mail.). )
另外，在错误日志中我收到如下消息；
04/10/2013 14:03:51,,Error,3617,The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 1 (2013-04-10T14:02:10). Exception Message: Cannot send mails to mail server. (Mailbox unavailable. The server response was: 5.7.1 Client does not have permissions to send as this sender).
在事件日志中我收到以下消息；
Exception Type: Microsoft.Sql.Server.Management.SqlMail.Server.Common.BaseException Message: There was an error on the connection. Reason: Timeout expired. The timeout period elapsed prior to obtaining a connection from the pool. This may have occurred because all pooled connections were in use and max pool size was reached.
我该如何解决？