Plugin "Heartbeat Control" Wordpress is working with heartbeats by default. Of course, you can deactivate or regulate heartbeats with plugins such as "Heartbeats Control". However, this is not advisable, as Wordpress subsists on heartbeats. Blog2Social works with heartbeats as well. Deactivating heartbeats prevents background tasks of Wordpress and Blog2Social from being executed completely. Thus, the plugin "Heartbeats Control" blocks post from being shared to social.
Please make sure, that the plugin is not set to "disable everywhere".