This resets around the 1st of each month. The COINS Translate App uses the Microsoft Azure Translator service as the engine for translations and we have a limit of 2 million character per month, which is shared by all users of our app. This is unsupported, but we do have other users who are using this method to give them more flexibility.
We have no commercial version of the app, but if you need to rely on the translation for your business, we recommend clicking the Help button that appears when the limit is reached, and it explains how you can create your own free Microsoft Azure Translator account which will give you your own personal 2 million character monthly limit.