Can receive Trackback but Pingback (in & out) not work

I have tested in https://www.tamba2.org.uk/wordpress/TestTrack/ for trackback and pingback.

Trackback is work. I can receive the tracback from TestTrack.

However, the pingback function is not working.

When I made a new post in TestTrack included my blog’s post permalinks .

My server log show below message:

[Mon Oct 3 00:39:08 2005] [error] PHP Warning: fopen(https://www.tamba2.org.uk/wordpress/TestTrack/2005/10/02/tes/): failed to open stream: HTTP request failed! HTTP/1.1 412 Precondition Failed\r\n in /vhome/public_html/wp-includes/functions.php on line 1831

I have checked the functions.php , I found it is related to the $fp = fopen( $uri, 'r' );

And my server have set allow_url_fopen .

Anyone know how to solve it ??

I have search here a lot post here which related to pingback but do not find something related it therefore I post my question here.

Regards
Ray