To configure the signing requirement for LDAP clients using the Group Policy Management Console:
Press Win+R, enter gpmc.msc in the displayed window, and press Enter.
This opens the Group Policy Management snap-in.
In the console tree, select Forest <domain name> → Domains → <domain name>.
In the context menu of the Default Domain Policy object, select Edit.
In the Group Policy Management Editor window, select Computer Configuration → Policies → Windows Settings → Security Settings → Local Policies → Security Options, and in the workspace, select the Network security: LDAP client signing requirements policy.
In the policy properties window, select the Define this policy setting check box and in the drop-down list below, select Negotiate signing.