Database backup is empty

Hi,
I have installed XCloner on 5 sites. In 4 sites it is working as expected, however in one small site, the database SQL-backup is empty as shown below:

#
# Powered by XCloner Site Backup
# http://www.xcloner.com
#
# Host: https://XXXXXXXXXXXXXXt.ch
# Generation Time: Dec 5, 2020 at 16:55
# PHP Version: 7.4.11
# Database Charset:
#
# Database : enXXXX_wp905
# ——————————————————–

#
# Finished at: Dec 5, 2020 at 16:55
#

Name of the database and the table prefix are correct. I can’t find an error message in the log of XCloner. It does not seem to find any tables. However, Backups with Softaculous and with Updraft are working fine, so I assume the problem is not with the database.

If I do the backup with softaculous, it works and the SQL-backup starts with the following entries:

— Softaculous SQL Dump
— http://www.softaculous.com
—
— Host: localhost
— Generation Time: December 5, 2020, 6:17 pm
— Server version: 5.7.32
— PHP Version: 7.3.6

SET SQL_MODE=”NO_AUTO_VALUE_ON_ZERO”;
SET time_zone = “+00:00”;

/*!40101 SET @OLD_CHARACTER_SET_CLIENT=@@CHARACTER_SET_CLIENT */;
/*!40101 SET @OLD_CHARACTER_SET_RESULTS=@@CHARACTER_SET_RESULTS */;
/*!40101 SET @OLD_COLLATION_CONNECTION=@@COLLATION_CONNECTION */;
/*!40101 SET NAMES utf8mb4 */;

—
— Database: enXXXX_wp905
—

— ——————————————————–

—
— Table structure for table wpqu_actionscheduler_actions
—

CREATE TABLE wpqu_actionscheduler_actions (
action_id bigint(20) unsigned NOT NULL AUTO_INCREMENT,
….

Thank you in advance for your help.