Without seeing what error message you are receiving, it is difficult to be certain; however, the Java update to 1.7_55 should be considered as the primary suspect. Any Java version higher the version 1.7.45 has been modified to use a different certificate structure.
If you are using any version of SiteScope below 11.23, your version has become non-operational because of the new Java versions.
If this occurs, you have two methods to solve the issue as follows:
* Downgrade your version of Java to a version earlier than 1.7_45. Make sure you turn off automatic Java update or then next time Java update, you will find your are back at this issue.
* Upgrade to SiteScope 11.23 or higher. This is the recommended fix. Make sure that your version of LoadRunner or Performance Center is supported by SiteScope version 11.23. You can check the HP Product Availability Matrix (PAM), usually found in the product readme files to verify version compatibility.