Hi gviks, I am not sure if we are able to help you with this.

If you are asking about the password saved on Firefox that is easy to change as necessary

• Please see Password Manager - Remember, delete and edit logins and passwords in Firefox

If as you appear to be saying you actually changed the password needed on a particular website then that is not a Firefox support issue.
You need to reset or change the password on the website in question.

The procedures vary. Some websites will not allow you to reuse passwords, or not withing a certain time frame. Some will force you to review and change passwords on a regular basis. All websites will have some method for changing or resetting passwords but the hoops needed to be jumped through will vary, and on some sites changing passwords; or resetting passwords, without knowing the current one; may result in data loss.

OOPS ! Sorry I just realised you appear to be asking about a problem seen on an Android smartphone.

The help articles relating to Android are:

• Manage saved passwords in Firefox for Android
• Using Master Password on Firefox for Android