Reconfiguring the email account may solve the problem for you. Here are the steps that you have to follow to reconfigure your email account.
First of all Right click on the account as displayed on the folder pane. Select the Remove account. It will ask for confirmation then click yes to confirm. After that you have to select the Add e-mail account link which is there at lower right corner of the screen. Type the email address and the password in that. Mark on Set this account as the default mail account as per your preference. Click on finish button to finalize the process.