Header issue

Hi, I’m running wordpress version 5.6, with popup version 1.9.56 and it runs great. When I try to update the popup version to 1.10.2, I get the header warnings below and the popups no longer work. The same issue persists even if I change to the 2020 theme.

Any help would be appreciated to resolve this so that I can use the latest version of the plugin. Thanks

Error messages:
Warning: Cannot modify header information – headers already sent by (output started at /xx/xx/public_html/wp-content/plugins/popup-by-supsystic/classes/fieldAdapter.php:622) in /xx/xx/public_html/wp-includes/functions.php on line 6360

Warning: Cannot modify header information – headers already sent by (output started at /xx/xx/public_html/wp-content/plugins/popup-by-supsystic/classes/fieldAdapter.php:622) in /xx/xx/public_html/wp-admin/includes/misc.php on line 1310

Warning: Cannot modify header information – headers already sent by (output started at /xx/xx/public_html/wp-content/plugins/popup-by-supsystic/classes/fieldAdapter.php:622) in /xx/xx/public_html/wp-admin/admin-header.php on line 9