NACHA is a company that processes an electronic payment system called the Automated Clearing House Network (ACH). It is a legitimate company. But if you, like I, received an official appearing email purporting to be from NACHA informing you that an electronic transaction you did from your bank account was rejected, you should immediately delete the email and not click on the link to a Transaction Report that will download malware on to your computer if you click on the link.
I am sure that many of you, again like I, use electronic payments and might be tempted to respond to the email by clicking on the link, however, some of the telltale signs that this is a scam is the lack of any information other than your email address that indicates that this email relates to you. Perhaps the most telling sign, however, is that with a little research, you would find that NACHA does not send communications in any form whatsoever to people about individual ACH transactions. Never click on a link unless you are absolutely sure it is legitimate and have done your research. In this case, I did it for you.