Cannot start session when headers already sent in

Hi, Our hosting provider is saying your plugin is generating a lot of errors. They send me the log and here are some of the lines:

[11-Feb-2022 05:06:26 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19
[11-Feb-2022 05:07:27 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19
[11-Feb-2022 05:07:40 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19
[11-Feb-2022 05:08:26 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19
[11-Feb-2022 05:09:39 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19
[11-Feb-2022 05:11:20 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19
[11-Feb-2022 05:11:34 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19
[11-Feb-2022 05:12:25 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19
[11-Feb-2022 05:13:37 UTC] PHP Warning: session_start(): Cannot start session when headers already sent in /home/quaffoqn/public_html/wp-content/plugins/templatesnext-toolkit/inc/woo-compare-wishlist/includes/compare/compare.php on line 19`
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Is there a fix for this?

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