Description:
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Sorry for my english

When i want to do a mail copy by imap_append, imap_append return false if the attachment(s) exceed approximately 900 Ko.
If the attachment(s) dont exceed the 900 Ko, imap_append return true.


Reproduce code:
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<?
$stream=@imap_open("(localhost:143)","$login","$password")
$boundary = "------=".md5(uniqid(rand()));
$header = "MIME-Version: 1.0\r\n";
$header .= "Content-Type: multipart/mixed; boundary=\"$boundary\"\r\n";
$header .= "\r\n";
$file=c:/file_name;
$ouv=fopen ("$file", "rb");$lir=fread ($ouv, filesize ("$file"));fclose ($ouv);
$attachment = chunk_split(base64_encode($lir));
$msg2 .= "--$boundary\r\n";
$msg2 .= "Content-Transfer-Encoding: base64\r\n";
$msg2 .= "Content-Disposition: attachment; filename=\"$file\"\r\n";
$msg2 .= "\r\n";
$msg2 .= $attachment . "\r\n";
$msg2 .= "\r\n\r\n";
$msg3 .= "--$boundary--\r\n";
imap_append($stream,"{".$serveur_mail."}Sent Items","From: expediteur\r\n"."To: vinvin@raouldomain.com\r\n"."Subject: sujet\r\n"."$header\r\n"."$msg2\r\n"."$msg3\r\n");
imap_close ($stream);
?>

Expected result:
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Normally, imap_append would have send the message with attachement(s) in Sent Items box same when the attachment(s) exceed approximately 900 Ko

Actual result:
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If the attachment(s) exceed approximately 900 Ko, imap_append not send the message in Sent Items box