If one company is reporting that they are receiving the following message, is the problem on their end? (They are asking us to fix the situation)
"This is the Postfix program at host xx.xxx.xx.xxxxx.com.
I'm sorry to have to inform you that your message could nto be delivered to one or more recipients. It's attached below.
email@example.com: [xxxxxx.com]: Name or service not known"