If your Instagram business accounts are all grouped under one Instagram login (called "Single login"), you can login and access up to 5 Instagram accounts inside the Instagram app. However, you won’t be able to use these same credentials to connect all of your accounts to Publish. This is because the Instagram API needs a unique username and password for each Instagram account that you want to connect to Publish.
Instead of using your single login credentials, you’ll need to use the username and password of the specific Instagram account you would like to connect. If you can’t remember the username and password, please follow the steps here to reset this.
Once you have the username and password, please go back to your computer desktop and connect your Instagram account using the steps in this guide.
We also recommend learning how to work with multiple Instagram accounts.