Why Mac Vers.2.4 UP Studio Show "Please Activate" all the time?

For the users using Mac Version 2.4 UP studio,When the software reminder you activate,

You need download the LKD2.4 file and Activate the software by import the downloaded LKD file to finish the activation. 

Download link for the LKD file:

https://www.tiertime.com/downloads/software-archive/#1508752224139-b5450a1f-f3c4

Mac Version 2.4 download link:

https://s3-us-west-1.amazonaws.com/…/d…/Up_Studio_V2.4.0.pkg.