Yandex, Bing and Google require keys. They use the keys to identify users, in order to limit the amount of translations that each user can request per month. If the limit is reached, they stop working temporarily. As the limit is high, it is unlikely to be reached. Please add keys for the translators you would like to use below.
WARNING: Daily Yandex API limit reached. Please wait until tomorrow or change API key
WARNING: Monthly Yandex API limit reached. Please wait until next month or change API key
Note:
If you need help with getting a key, watch the Tutorial on How to Configure Mind the Word on YouTube. You can watch other tutorials
here.