Please note that some accounts have restriction these are set by Facebook not us

Facebook services have some restrictions about posting and getting data about pages. If you reach limit you will get notification about it. Usually, if that happens you should wait about an hour and Facebook services will work again. 

Each page has different restrictions depending on the number of daily engaged people. For pages with a large number of daily engaged people restrictions are small. The number of daily engaged people using a page is the unique number of people who have interacted with the page in a 24-hour period. An interaction with a page consists of a click on the page or page content. 

If you turn on Facebook analytics you will probably reach limit faster and maybe some of your scheduled posts will not be posted.