This article will explain how to delete a third party email account from 123-mail webmail.
Login to the 123-mail webmail.
Click on the Configuration icon in the main toolbar.
Click on the E-mail folder in the left hand pane.
Click on the subfolder Accounts
Click on the Account you wish to remove.
Click on the Delete button under the E-mail Accounts tab.
Click on Yes to confirm the removal of the account.