Hello/Hi/Greetings,

I am trying to add new users and send a notification email to them with their username and password. I am getting an error email with the following text. Can anyone help me understand what I may be doing wrong? Thanks in advance.

This is the mail system at host piwigo.com.

I'm sorry to have to inform you that your message could not
be delivered to one or more recipients. It's attached below.

For further assistance, please send mail to postmaster.

If you do so, please include this problem report. You can
delete your own text from the attached returned message.

                   The mail system

<rlwysocki@gmail.com>: host gmail-smtp-in.l.google.com[66.102.1.26] said:
    550-5.7.26 This mail has been blocked because the sender is
    unauthenticated. 550-5.7.26 Gmail requires all senders to authenticate with
    either SPF or DKIM. 550-5.7.26  550-5.7.26  Authentication results:
    550-5.7.26  DKIM = did not pass 550-5.7.26  SPF [tyca.com] with ip:
    [87.98.133.140] = did not pass 550-5.7.26  550-5.7.26  To mitigate this
    issue, please visit Gmail's authentication guide 550-5.7.26 for
    instructions on setting up authentication: 550 5.7.26
    https://support.google.com/mail/answer/ … entication
    k29-20020a05600c1c9d00b0040b3f116f39si474089wms.165 - gsmtp (in reply to
    end of DATA command)

(Piwigo 13.8.0)
Piwigo URL: http://tyca.piwigo.com