Unfortunately Schedugram does not support Instagram's two-factor authentication at this time.
The reason we don't support it is because of how we work: because we use our pool of devices to post customers' posts, we aren't able to leave you "logged in" to one of the devices at all times. If we did, we would need one device for every account that you added (but we do for enterprise customers who sometimes need approaches like that), which would add up very quickly and the service would cost a lot more to provide to you!
If we work out a way to be able to support it, rest assured that we absolutely will roll it out to customers. We want your account to be as secure as possible just as much as you do! But at the moment, the way that our service operates makes it impossible to do so.
Note that we do support being able to set up two-factor authentication for your Schedugram account login – some of our larger customers require it for their IT compliance. But that's different to your Instagram account having two-factor authentication.