Symptoms

Message sending fails with error:

451 qq read error

Cause

This error is returned by SMTP service, and there could be several reasons for it:

  1. Antivirus software installed on qmail node
  2. Lack of free space on qmail node.

Resolution

  1. disable antivrus
  2. free up some diskspace (free space can be checked with df -h command)

Internal content