[Read Mail] What does the "Unknown Sender" mean in the Read Mail page?
"Unknown Sender" is shown only next to emails that have not been verified.
Unverified emails are defined as emails that are supposedly sent by the shown sender account, but in actuality was not sent through the sender's server. In other words, the email has been send with a different sender account.

Sender accounts can be changed for many reasons.
However, spammers change sender accounts to send fraudulent emails, so the "Unknown Sender" message is displayed to caution email recipients.

The message may also be displayed on non-spam mails, so please be cautious when opening emails and do not press the link or open attachments if the mail looks suspicious.

Please click [Block Spam] to report a spam mail.