Hi, Clicking on configuration button it displays the configuration page with all characteristics. But when when I select or change the value for characteristics I am getting session not found exception

Error message

java.lang.IllegalStateException: Session does not exist and could not be retrieved at de.hybris.platform.sap.productconfig.runtime.ssc.impl.BaseConfigurationProviderSSCImpl.retrieveConfigSession(BaseConfigurationProviderSSCIm pl.java:574) at de.hybris.platform.sap.productconfig.runtime.ssc.impl.CommonConfigurationProviderSSCImpl.fillConfigModel(CommonConfigurationProviderSSCImpl .java:52) at com.sap.projects.custdev.fbs.slc.impl.ConfigurationProviderSlcImpl.fillConfigModel(ConfigurationProviderSlcImpl.java:448) at de.hybris.platform.sap.productconfig.runtime.ssc.impl.BaseConfigurationProviderSSCImpl.retrieveConfigurationModel(BaseConfigurationProvider SSCImpl.java:392)