The term bandwidth limit exceeded means that the amount of bandwidth that was allocated to the hosting plan has been reached.
Bandwidth is consumed when data is retrieved from the server and delivered to the end user (outbound traffic) as well as when the end user uploads data to the web server (inbound traffic).
All data sent from the site to the client and vice-versa gets accounted for as bandwidth usage. If the amount of bandwidth used exceeds the amount of bandwidth allocated by the web host, the browser will return a bandwidth limit exceeded error.
You will have to investigate the cause of high bandwidth usage and optimise the elements of your website or upgrade to a hosting plan with higher resources.