Why am I getting email duplicates from Niconico?
If you are receiving duplicates of email notices from Niconico,
it could be due to the following:
・Emails are being forwarded with email software or another program
・Email copies are configured to periodically remain on the POP3
server and multiple instances of an email are being downloaded
・The server responsible for email delivery is resending for an
Also keep in mind that the same email is sent to each email address
registered with Niconico.