1、the java-agent and ACTIVATION_CODE can get from this site:https://zhile.io/2018/08/25/jetbrains-license-server-crack.html
2、delete the fucking folder .GoLand2019.3 or other product-config if it exists.The path is C:\Users\your-computer-name. Example: C:\Users\ww.
3、reopen or reinstall. After that you will see this : 
4、click OK ,see :
5、Skip , for avoiding trouble .see:
6、choose evaluate for free, click evaluate , then click continue. After that you will see this :
7、do not fucking click new project or open project !!!
do not fucking click new project or open project !!!
do not fucking click new project or open project !!!
click Configure :
8、choose Edit Custom VM Options.. ，fill in the right javaagent path ,then click save, then exit
9、 reopen it, Then click Configure , choose ,Manage License...
10、 see this :
10、fill in the right ACTIVATION_CODE which get from ACTIVATION_CODE.text:
11、 Oh ,fucking it! congratulations. Have a joy.