Where can I get this certificate?

Question

PHP

For the web directory of the organization's employees with their mailboxes, we had a php script connected to kerio and fetched data. For some time now, the data has stopped updating and an error has appeared in the logs

ldap_bind(): Unable to bind to server: Strong(er) authentication required in...

On php.net itself or in SO they talk about a certificate that needs to be placed in a certain folder, tweak something and everything will work. But I can’t understand from the context what kind of certificate it is and where to get it? Here are examples of solutions where it is mentioned:
php.net/manual/ru/function.ldap-start-tls.php
https://stackoverflow.com/questions/43422469/php-a...
Environment where the script runs: MS Windows, php 5.4.9.
ps answering and commenting: the question is NOT about http/https.

Answer 1

As I understand it, you need an SSL/TLS certificate. If your site works on http, then you need to work on https. But this is not accurate, experts, please correct me if I'm wrong.

Answer 2

See the Kerio documentation for how to download its public key.
Since the system worked for you before, look on the disk where your site is located for the ldap.conf file.
It contains the line
TLS_CACERT path\to\your\CA\cert\file.crt
Update it.
Perhaps in Kerio itself, you first need to reissue the key.