There are different reasons for different campaigns. To troubleshoot, or to know the reasons, go to “reports’, and check the status of the concerned campaign. If the status is ‘Complete’, then go to ‘Logs’ and find the campaign. In the last column you would find the reason for not creating posts. Most of the time ‘keyword not present in the title’ is the reason for failing campaigns. In this case, try another keyword or keyword phrase. Alternatively, you can open the feed URL in your browser and check if the keyword is present or not.