When I was younger, I ran ops for a small ISP in Maine. At some point technical support was outsourced to a company in the south. We were having an issue with certain users not being able to auth to the SMTP server, or so I was told by the owner of the call center. I couldn’t reproduce the issue, nor get him to provide me the name of a customer that was having the problem. I eventually discovered he was giving users the ip address of his mail server as his “solution.” However, in the interim, he yelled at me about how much experience he had, then a week or two later, he died.