Error: Python smtplib cc Not Working

What's Causing This Error

Sometimes, your email may be received successfully, except for the emails you declare as CC. A possible cause for this issue is that you are adding the emails to the message correctly but not adding the CC to the envelope.

Solution - Here's How To Resolve It

In such cases, when sending the email, try using the ccaddr with the toaddr.

For instance, consider the second parameter of the sendmail() method.

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s.sendmail(fromaddr, toaddr+ccaddr, msg.as_string())

According to the documentation (link below), the message envelope gets created using the first two parameters (fromaddr and toaddr). So, adding the ccaddr to it will solve this issue and successfully send the email to CC recipients.

Read more here.