Due to App uses a non-API connection with Instagram (which is against the Instagram security policy) - I wasn't able to post anything on my feed. Instagram blocking the app and showing me a warning in the official Instagram App "Unusual activity" or "You shared your password with someone, you must change it now, never share your password with third-party apps or websites".

If Prostoplan will use an official Facebook API (for Instagram business accounts) - Instagram will not block and it will work. The only thing - API doesn't allow you to post stories (probably that's why Prostoplan asking to provide an Instagram password, which is against the Facebook/Instagram policy and it's not safe for big accounts). I have Instagram with more than 1M followers and I never would add it by sharing passwords. I've tested on a small account.

If Prostoplan will add a legal way to add Instagram - that would be awesome. It's not hard.

On my question about this issue I've got a very unprofessional answer, just read it: "It is normal practice when you log into your Instagram from a new device. For example, you take a friend's phone and want to log into your account. To do this, you will enter your username and password. Right? It's the same here. " - it's not the same if you not using an official Instagram App or Website. For all the developers Instagram has an API that works in Hootsuite and other third-party planners.

Be careful, because Instagram/Facebook may sue companies that are collecting passwords (even if you may say you are not - when anyone entering their password on your website - legally it's an act of sharing the password).