Message rejected for spam or virus content - all emails being blocked
We have a dedicated Centos server with GoDaddy which has been running a business app for about 8 years. On Monday around 11:00 am we started receiving outbound email failures centered around - Message rejected for spam or virus content - about 90% of our emails are blocked and not always to the same email address -- sometimes works, some times not. The logs are full of sending errors with no consistency in time. We have checked to make sure no server changes occurred on Monday or any domain config changes or email settings or anything -- but this is still happening. If anyone can suggest where to further explore -- we have even simplied the content to be TXT only email with no images, tags, attachments, URLs, etc -- no change in the rejections.