Duplicate mails, also Email test

Replies: 0

Hello! I´m facing an issue that we´re receiving duplicate emails from orders (woocommerce) and if I send an Email Test it´s delivered three times!
I´m also having this is the error in the Debug:

Email Source: WP Core
Mailer: Other SMTP
SMTP Error: The following recipients failed: rafael@mixtepijamas.com.br: : Recipient address rejected: User unknown in virtual mailbox table
financeiro@mixtepijamas.com.br: : Recipient address rejected: User unknown in virtual mailbox table
expedicao@mixtepijamas.com.br: : Recipient address rejected: User unknown in virtual mailbox table
comercial@mixtepijamas.com.br: : Recipient address rejected: User unknown in virtual mailbox table
marketing@mixtepijamas.com.br: : Recipient address rejected: User unknown in virtual mailbox table

Do you know what might be the cause of this? Thank you!