Free account submission limit

With a free account, you can receive up to 100 submissions per month. If you already reached your limit for a certain month, you have to wait until your submissions counter resets to zero which will be on every first day of the following month. If that happens, you can upgrade your account to any paid plans to get higher limits and to continue receiving submissions. You can check this guide for more information: Understanding Your Account Usage and Limits. 

I hope this will help. Let us know if you need further assistance.