FOOBox stopping backup plugins from working

Hi I have been using a backup to dropbox plugin called Backwpup for many years but it has now stopped working on several of my sites. The error messages all mention Foobox (see below). On this site I uninstalled Backwpup and reinstalled it but when I try to reconnect it to my dropbox I get the the same errors I got when trying to run the backup. I tried an alternative backup plugin called Backup & Restore Dropbox and got the same errors. I contacted the Backwpup people who said the issue is with Foobox. This site is hosted on Siteground but other affected sites are on 1and1. Can you please advise me. Thank you.

Warning: Invalid argument supplied for foreach() in /home/learntea/public_html/multimindeddigital.com/wp-content/plugins/foobox-image-lightbox/freemius/includes/managers/class-fs-admin-menu-manager.php on line 493

Warning: Invalid argument supplied for foreach() in /home/learntea/public_html/multimindeddigital.com/wp-content/plugins/foobox-image-lightbox/freemius/includes/managers/class-fs-admin-menu-manager.php on line 493

Warning: Cannot modify header information – headers already sent by (output started at /home/learntea/public_html/multimindeddigital.com/wp-content/plugins/foobox-image-lightbox/freemius/includes/managers/class-fs-admin-menu-manager.php:493) in /home/learntea/public_html/multimindeddigital.com/wp-admin/includes/misc.php on line 1116

Warning: Cannot modify header information – headers already sent by (output started at /home/learntea/public_html/multimindeddigital.com/wp-content/plugins/foobox-image-lightbox/freemius/includes/managers/class-fs-admin-menu-manager.php:493) in /home/learntea/public_html/multimindeddigital.com/wp-includes/pluggable.php on line 1216

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