Deactivating your plugin is not the same as deleting it (read more).
If your CoSchedule account is not connecting to your WordPress site, deactivating and reactivating your CoSchedule plugin can refresh the connection.
Go to the Plugins tab inside of WordPress and find CoSchedule. Click Deactivate to temporarily deactivate your plugin.
After your plugin deactivates, click Activate. CoSchedule will bring up a sign-in window. Sign back into your CoSchedule account.
If you are able to navigate your calendar and post, your CoSchedule account is connected with your WordPress blog. If there is still a connection error, contact support at Support@CoSchedule.com.
Upon successfully reactivating the plugin, social messages that are still left to publish will resume according to the schedule you previously set up.