Are you trying to put a long message into the Starbase Message of the Day? There is a 200 character limit to the message. If you try to put in more than 200 characters, the system will not update the MoTD. You can check if the system took the change by closing the UI and re-opening the UI to see if the message has changed.
Also, when you type in a message that is over 200 characters long, the system does not chop off the text beyond the 200 characters. Instead, the system will keep the older message.