"User XYZ inactive"

Hello,

can someone please help me with a licencing issue that I have? I am the technical lead for a Formula Student Team and some of my new collegues have access to the web interface, but as soon as they want to open apps like part design an error occures which states that the user is inactive. 

Is there a way that I can help fix this issue or how do these people get the access they need?

Edu SOLIDWORKS