return information from email submit

I am having trouble sending email to a bcc list. The same form sends a message to an individual user but as part of a bcc list the send fails. I can detect that with
$this->get('email90'); which returns true or, in this case, false. The form has worked up until this last week. 😡
Is there any way that I can get more data from
$this->get('email90') other than the boolean that might help me track the problem?
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Regards Nick

No, because that boolean is all Joomla itself returns. Maybe check and make sure the BCC list is filled with only unique addresses.

thanks. I will check that out. I just may have the same addresses in cc and bcc