There is an alternative,  the manual Backup

You must perform the below tasks:

1. export the DB using PHPMyAdmin
2. take backup the dirs

• modules
• profiles
• sites
• themes

In order to restore or migrate

1 create a new DB and import the export

2 restore the 4 dirs, to the Drupal root dir

3 extract to another dir the Drupal.???.zip

4. Copy all the staff except the 4 dirs to the root dir of the new installation

5. Go to setting.php ar ROOT DIR Drupal 8>sites>default>settings.php

6. ADD settings[update_free_access] = TRUE

7. Run the /mysite/update.php

8. log in as admin

9. delete the line from settings.php

settings[update_free_access] = TRUE

10. From reports run the

1. status report
2. available updates

11. update the site, if it is needed

12. take a fresh backup

 

Always read the documentation of Drupal.