On the Pro Plan.

I am using a simple automation to send emails to static addresses.  The process is functioning well and emails are successfully sent to any address correctly entered into the To: field of the automation.  However, there is one exception.  The process will not send to one specific email address (sales@xxxxx.com).  No email is ever received.  It does not go to the Junk box: Airtable automation history says the message was sent.  This is particularly odd because this is the email address used as the login for the whole account!  It is happening in several different automations.

  In the attached screenshot the email to diane@xxxx.com was received.  There is no sign of the one going to sales@xxxx.com.  The automation history says it was sent.

Any ideas?