This article describes how to reconfigure, or remove and re-add, the Native Mail Client on a Mac.
1. Open the Mail App. You may have to locate the Mail App using Finder.
2. In the tool bar, click on "Accounts."
3. Find your Exchange account. It should show the email address email@example.com
4. Remove this Exchange mail account by clicking the "-" at the bottom of the window.
5. Add the updated or new Exchange account back by clicking "Add Account."
6. Choose a mail provider.
7. You will need to enter your email address (firstname.lastname@example.org)
8. You will be asked to manually configure or sign in to complete the creation of the account and you want to click "Sign In."
9. Now you will need to enter the password associated with your email account.
10. Your permission will be requested in order for the Mail App to access your information. You need to click "Accept."
11. Select the apps you would like to use with this account.
12. Click "Done."