KantanMT's subscription is based on the language pairs you as a user configure. Therefore in the Kantan screenshot below, KantanMT can only be used for 3 language pairs; English->Greek, English->French and English->German.
To setup KantanMT service you also need to provide an engine alias as seen below:
When you create an engine on KantanMT interface you will also provide this engine alias. In case you already have an engine you can edit the alias. It is recommended to use the same engine alias for all the language-pair KantanMT engines you want to use with Transifex. For more details on how to setup a KantanMT engine see here.
There is an initialisation period required for KantanMT of roughly 6-7 minutes and the Machine Translation Engine runs for 15 minutes at a time. This means that if someone attempted a machine translation when the KantanMT engine was not running they would receive the error in the screen below:
6-7 minutes later the KantanMT engine will be initialized and the user can machine translate. After 15 minutes of not being used, the engine shuts down again. The same behaviour applies when you use auto-machine translation.