Warning message with every posts publish

Hi everyone,

I have a problem when I publish a post. I had this problem from the beginning and I don’t know what it is causing. I normally got that Warning message whenever I finished a post and published it but it doesn’t cause any problems. Nevertheless I would like to understand this warning and get rid of it as it may will cause problems in the future.

Here the warning message:

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Warning: count(): Parameter must be an array or an object that implements Countable in /homepages/29/d751027505/htdocs/clickandbuilds/cellution/wp-content/plugins/social-media-auto-publish/admin/publish.php on line 1002

Warning: Cannot modify header information – headers already sent by (output started at /homepages/29/d751027505/htdocs/clickandbuilds/cellution/wp-content/plugins/social-media-auto-publish/admin/publish.php:1002) in /homepages/29/d751027505/htdocs/clickandbuilds/cellution/wp-admin/post.php on line 210

Warning: Cannot modify header information – headers already sent by (output started at /homepages/29/d751027505/htdocs/clickandbuilds/cellution/wp-content/plugins/social-media-auto-publish/admin/publish.php:1002) in /homepages/29/d751027505/htdocs/clickandbuilds/cellution/wp-includes/pluggable.php on line 1223

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Do you know why this occurs?