Here, I am Recommending you the best possible method to reset you e-mail account on kindle....
Follow these step :
1. Swipe down from the top of the Home screen to display Settings.
2. Tap My account.
3. Tap My Account.
4. Tap Manage E-Mail Accounts
5. Tap Add Account.
6. Tap AOL, Exchange, Gmail, Hotmail, Yahoo!, or Other Provider.
7. Enter your username, e-mail address, and password in the appropriate fields, and then tap Next.
8. Enter the name that will appear on outgoing messages in the Name field and an address in the E-Mail Address field for your e-mail account.
9. Enter the password for your e-mail account in the Password field.
10.Tap the Send Mail from This Account by Default check box if you want to set this up as your default e-mail account, and then tap
1. If a message appears about how some accounts sync with your Kindle Fire HD, tap OK to proceed.
12. In the final screen, tap Save and then tap the View Inbox button to go to the inbox for the account you just set up.
You can set up as many e-mail accounts as you like. When you open the Kindle Fire HD Email app, you see a Unified Inbox that combines messages from all accounts you set up, as well as individual inboxes for each account.
If you don’t get satisfied with the solutions, you can go for the professional help by just visiting here :
www Kindle Com Support | Kindle Tech Support | Kindle Help.