Only drop connection if user originally bound to this backend,
and rebind-as-user was set. Sessions from other backends would
use idassert-bind so loss of creds doesn't affect them.
                        op->o_tag = o_tag;
                        rs->sr_text = "Proxy can't contact remote server";
                        send_ldap_result( op, rs );
-                       rs->sr_err = SLAPD_DISCONNECT;
+                       /* if we originally bound and wanted rebind-as-user, must drop
+                        * the connection now because we just discarded the credentials.
+                        * ITS#7464, #8142
+                        */
+                       if ( LDAP_BACK_SAVECRED( li ) && SLAP_IS_AUTHZ_BACKEND( op ) )
+                               rs->sr_err = SLAPD_DISCONNECT;
                }
 
                rc = 0;
 
                ldap_back_release_conn( li, lc );
        }
 
-       if ( rs->sr_err == LDAP_UNAVAILABLE )
+       if ( rs->sr_err == LDAP_UNAVAILABLE &&
+               /* if we originally bound and wanted rebind-as-user, must drop
+                * the connection now because we just discarded the credentials.
+                * ITS#7464, #8142
+                */
+               LDAP_BACK_SAVECRED( li ) && SLAP_IS_AUTHZ_BACKEND( op ) )
                rs->sr_err = SLAPD_DISCONNECT;
        return rs->sr_err;
 }