Hello @COREstudio ,
Per Facebook's API restrictions, Instagram business profiles need to be connected to a Facebook business manager / admin. Therefore you'll need to login to the personal Facebook account that is setup as an admin of a Facebook or Insta business page.
I'd also recommend checking these articles as they all cover some aspect of connecting your Instagram business profile to Constant Contact:
Support Tips
"There's a multitude of ways to engage your audience through us using your social platforms - via ads, social post metrics, email links, and more! " - Will
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"Target your most engaged contacts by creating a segment. Create a special offer or show your appreciation!" - Caitlin
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"Greet new contacts with one or more automated Welcome Emails depending on their interests or your business goals." - Nick
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