• Kindly check timer expiration date (End repetition at OR Expires at) under 'Timer Settings' section. This date should be in future.
• Check if the position you've setup is correct. If you have selected 'custom' position, make sure you provide a valid html selector.
• In case of repeat timer, make sure you setup valid start and end dates and enter appropriate values in Day(s), Hour(s) and Minute(s) fields.
• Make sure 'Display Page Settings' are correct and you're checking it on your store as per your configurations.
• Make sure you've enabled the timer :)