Search api solr: The Solr server could not be reached I've got a working solr server, however my drupal always fails to connect, what am I doing wrong?

When adding my server and clicking on the solr server url it takes me to my server (so my path is correct), yet I keep getting a message: The Solr server could not be reached.

I am hosting apache solr on a server (not locally).


Host: Server IP address
Port: 8983
Instance: /solr


Can anyone help me out ?
@see &quot;Your site was unable to contact the Apache Solr server&quot;

I follow this article https://www.lullabot.com/blog/article/installing-solr-use-drupal ,some day comes this errors after I reconfig of my site&amp; apache.
but I sloved like this