KernelCurry on "[Plugin: nrelate Related Content] Use of undefined constant NRELATE_API_ONLINE"

Notice: Use of undefined constant NRELATE_API_ONLINE - assumed 'NRELATE_API_ONLINE' in /var/www/.../plugins/nrelate-related-content/admin/nrelate-admin-settings.php on line 317
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Easy fix, would just be nice to not see it when I am in debug mode.

https://wordpress.org/plugins/nrelate-related-content/