Simple Org Chart error after installed.

hello, I just want to ask. What would be the problem in my WordPress site?
because after I install the “Simple Org Chart” the error message pops up.

— here is the error —
header information – headers already sent by (output started at /home2/psewebdev/public_html/wp-content/plugins/simple-org-chart/index.php:726)

Thank you!