To be able to connect your LinkedIn Page, your personal LinkedIn Profile must have the role of super admin of the page. FYI a super admin role is automatically granted to the creator of a LinkedIn Page.
If you’re still not sure whether you have admin access to a LinkedIn Page, head to the page’s URL. If you are designated super admin, you will see a tab that says Super admin view next to the brand’s name in the top left hand corner.
If you do not see that, look for a blue tab that says View as admin. If both of those options are missing for you, you may wish to request admin access:
List your current position with the organization on your profile. This step is required.
Go to the Page you’d like admin access to.
Click the More icon and select Request admin access from the dropdown.
Click the checkbox to verify that you’re authorized to become an admin of the Page.
Click the Request access button. You’ll see a notification indicating that your request was successfully sent. This grants all current super admins access to your public profile information.
You'll receive confirmation in your Notification tab once you've been assigned Page admin access.