SSRS sub report not visible while rendering

We need to verify the Hidden property in the visibility section and make sure it is said to false (hidden=false). Remove the expression and try hardcoded values like true or false. Make sure all the parameters defined in the sub report are properly associated in the main report. One of the reasons is if the sub report is having dataset associated to it and the dataset is not returning a single record will be a problem. Otherwise the record may contains all null values.