One of the world’s largest media and telecom companies had to apologize to thousands of its customers because of an email snafu by one of its suppliers.

A Virgin Media supplier mistakenly sent out a message that if replied to via the ‘reply all’ option would then be sent to all others in the group, according to a report by The Daily Mail.

If a customer who received the email replied to all, their individual email address would be visible to all recipients to see. This issue only affected those with a Virgin.net account. More than 130,000 people may have been affected by the gaffe.

According to a statement by a Virgin Media spokesperson, the company apologized for the breach and is currently investigating the matter. It strongly encouraged users to not reply to the email.


[A previous version of this article has been updated to indicate that only customers who replied all to the message would have their individual email address visible to recipients.]