进行倾向匹配得分时无法安装psmatch2统计包，输入ssc install psmatch2后一直出现：

connection timed out -- see help r(2) for troubleshooting
could not load psmatch2.pkg from http://fmwww.bc.edu/repec/bocode/p/
r(2);


请问如何解决？