SMTP protocol synchronization error (next input sent too soon: pipelining was not advertised)

在某些硬體spam 設備做將被隔離的信件撈回動作時, 會被exim 擋掉
錯誤訊息如下
SMTP protocol synchronization error (next input sent too soon: pipelining was not advertised)

可以將exim 的檢查選項關閉

default 是開啟的

在main configure 內

加入
smtp_enforce_sync = false

可避免再發生上敘問題