If your wallet is encrypted, message content is protected until you unlock your wallet. You will also need to unlock your wallet to send messages. To do this open the console vie Help > Debug Console. Navigate to the “Console” tab. In the textinput at the bottom of the screen enter:
walletpassphrase [password] [time]
Replace [password] and [time] with your wallet password and the time in seconds for which you want your wallet to be unlocked. After it is unlocked your message content will be visible (you will need to click the refresh button after unlocking), and you will also be able to send messages.