Firebase auth changePassword failing

Question

With one particular user this is failing. With any other user that I try it works, but for this one user not matter what I do this call fails with the "INVALID_PASSWORD" error.

firebaseRef.changePassword({
  email: <email-address>,
  oldPassword: <resettoken>,
  newPassword: <newpassword>
}, function(err) {
  // {"error":{"code":"INVALID_PASSWORD","message":"The specified password is incorrect."}}
})

I've tried

1. Using a simple password that worked for the same reset password flow with a different email address (rules out the possibility of the new password being invalid)
2. Sending the reset password email again and making sure to use the link with the most recent reset token
3. Going through the reset password flow on a different account (worked fine, several times)

Out of ideas here... it just seems to be this one account.

Answer 1

Turns out the receiver's email client was down-casing the href in the URL, this caused the token param to be incorrect (it's case sensitive)

This was the link my email template (plain text):

https://<mywebsite>.com/?email=%EMAIL%&reset_token=%TOKEN%

With that plan text url^ it appears that the one email this customer used down-cased the link. Solution is to add an html template:

<a href="https://<mywebsite>.com/?email=%EMAIL%&reset_token=%TOKEN%">https://<mywebsite>.com/?email=%EMAIL%&reset_token=%TOKEN%</a>