First things first, is your Instagram account setup as a business account?
please follow the instructions here: https://www.facebook.com/help/502981923235522
If yes or unsure,
you can check in Instagram. All you have to do is go to Settings > Privacy and Security > Security > Access Data > Business Profile Info. See screenshot below:
2. Once confirmed, make sure a Facebook page is created for the IG Business account. Go to Edit Profile > Profile Information > Page. You should be connected to a FB page here, if not please follow the prompts to do so. See screenshot below:
3. Next, use the link (provided by Keyhole) to authenticate your Instagram Business page. Make sure you are selecting the option below:
4. Here you will need to log into your account through Facebook, and provide Keyhole access to collect data. The next step will ask you to select the FB page and Instagram Account that you would like to give access to. If your FB page does not show up you here then either it is not correctly linked to your IG Business profile or you will need to remove it by logging into your Facebook account and selecting: Facebook > Settings > Linked Accounts > remove Keyhole). You will then need to go back and try again from the beginning.
5. Finally, if all steps were followed correctly, the Instagram Business account should be authenticated correctly and this message should be received. You will also see an 'Auth' banner on the authenticated account.