Connect Zohodesk to Instagram - not possible

Connect Zohodesk to Instagram - not possible

We have connected Zohodesk to Facebook without a problem. However, our Instagram account uses a different email/login which is NOT associated with any Facebook account.

Whenever I try to connect (even a different brand) to Instagram it brings up the Facebook login instead of the Instagram login.

How can I connect to Instagram directly and NOT via Facebook?

Thanks!