smtp; 550 Messages should have one or no To headers, not 2.

[musicjunk]

Hello Pedro,
I treid your work, but I get the error message and no email was submitted. I looked at the source code of the sended email and realy there are two entries of "To:" in the source. The first is without any mailaddress, the second with the mailaddress. I think that causes the error.
Here is a cut out of the source wth the two "To:"

To: 
Subject: =?UTF-8?B?TmFocmljaHQgenVtIEV2ZW50OiAgVGhlIEJlZSBXaWdzLCBGcmVpdGFnLCAyMi4gQXByaWwgMjAyMg==?=
X-PHP-Originating-Script: 10321:SimpleMail.class.php
MIME-Version: 1.0
To: <info@test.de>
Date: Tue, 05 Apr 2022 02:26:33 +0200

Can you please fix it. Or any one other has a suggestion for me to fix this.
Thanks

[madegit]

I also encountered this issue, and it seems in unattended to.