Help on configuring sending emails


Hello everyone,
It’s been 3 days since my code sent me an error each time I tried to send an email. I downloaded my application sylius in a production server and when I tried for example to confirm a command I get an error:

request.CRITICAL: Uncaught PHP Exception Swift_TransportException: "Failed to authenticate on SMTP server with username "contact@******.com" using 2 possible authenticators. Authenticator LOGIN returned Swift_TransportException: Expected response code 235 but got code "535", with message "535 Incorrect authentication data

Can you help me?