How do i remove the "via f69e.squarespace" tag in my email?

How do i remove the "via f69e.squarespace" tag in my email? I have tried inputing the following codes separately in my custom css but they all give a syntax error on line 2

.sqs-announcment-bar-meta {

    display: none;

}

.sqs-announcment-bar-message:after {

    content: "via f.69e.squarespace"

}

Thank you for the help!

Hi,

Can you take a screenshot of "via.." message? And what is your site url?