"Due to a recent outbreak of computer viruses being transmitted via e-mail messages, Yahoo! Groups is experiencing delays in delivering group messages," read the advisory. "To improve performance, and to help reduce the spread of viruses, Yahoo! Groups has had to temporarily reject some messages."
"We can assure you that this is only a temporary measure and hope to restore message delivery to normal as soon as possible," read the advisory.
Yahoo Groups will reject messages with the following subject lines: test, hi, hello, Mail Delivery System, Mail Transaction Failed, Server Report, Status Error.
Yahoo was unable to comment prior to publication of this article.