Due to a recent Facebook change, we've seen this issue reported for some users who are logged into Facebook as a business rather than a personal profile. Fix this by logging in as a personal Profile instead. Please try the following steps:
Go to facebook.com and log in as your business if you're not already.
Remove Ecamm Live from the list of business integrations.
On Facebook, go to Settings, and then Page Roles.
Ensure that your personal Facebook profile is an Admin for your Business Page.
If it is not, invite your Facebook profile to be an Admin.
Log out of Facebook and now log back into Facebook as your personal profile.
Accept the invitation to become an Admin for your business.
Now, in Ecamm Live, click the blue Login button and log into your personal Facebook account.
Pick your business from the Post as menu.