the system clock has been set back more than 24 hours.
Manu Start > Desktop > Advanced (ArcInfo) Concurrent Use > Change >"computer name" > OK
解决方案:开始-ArcGIS-License Manager-License Manager Tools-Config Services进行如图设置(若不存在些路径,请打开X:Program FilesESRILicensearcgis9xlmtools,10.0版本路径也类似,我以9.3版本为例,X为证书的安装路径)