PHP "Invalid Date: header (not RFC 2822)"

SpamAssasin complains that the date format is wrong.
0.4 INVALID_DATE Invalid Date: header (not RFC 2822)

Supplied date is:
Date: Sat, 30 Apr 2022 11:20:15 0200

as a result of mail PHP script code:
$this->_add_hdr('Date', sprintf(date(DateTime::RFC2822)));
or
$this->_add_hdr('Date', sprintf(date("D, d M Y H:i:s O")));

(it seems to display same format no matter which line i use)
Do you have an idea how that PHP code line should look like so the error does not appear? WordPress ...