[Django]-Stripe: Error "This application is not authorized to edit this account" while updating the account in stripe

In my stripe experience, I had the same error like you.
I looked the stripe documentation carefully and I found that I used the wrong user type.
As you know, the stripe has 3 user types. standard, express, custom.
What I’ve done wrong is I used the standard account type. It was wrong.
Only custom account can have external_account.

So I changed the account type as ‘custom’ instead of ‘standard’.

Here is my rails code below:

account = Stripe::Account.retrieve(current_user.stripe_account)
account.external_accounts.create(:external_account => params[:stripeToken])
account.save