From the 1st of February Autodesk changed dramatically how BIM 360 Team projects can be accessed.
Before, you could setup a project in BIM 360 Team and invite external partners to this project to work together with the project data. These external partners are called “Contributors” and were, until the 1st of February, for free.
But the access model has been changed. From now on everybody accessing a BIM 360 Team hub will consume a license…
Users that were invited to projects before the 1st of February will continue to have free access to these project until January 31st 2018.
There is one exception: you can still share a particular document with external users for free.
In that case you can send the user the link to this file and after clicking on this link the user can only view this particular document.