Thank you for reaching out to the Community! I apologize you are unable to connect your business page as you should. Is your personal page set as an administrator for your business page? You must be an Administrator for all of the social media accounts you're trying to link with Social Share. Once you are connected as an administrator you can follow the steps listed here to connect your page.
Frankie P. Community & Social Media Support
Did I answer your question? If so, please mark my post as an "Accepted Solution" by clicking the Accept as Solution button in the bottom right hand corner of this post.