Hello @BarbaraR904 ,
Are you getting any specific error messages, or does the issue only seem to be occurring for a particular platform or account? It looks like your account is showing all your posts as successful, have you been having to hit retry each time to get them to post successfully?
The issue was that posts that were scheduled to go out on a certain day and time were not sent, but also did not show an error indicating as to why it did not send. The post remained in a scheduled status even though it was long past the originally scheduled time, thus I had to go in and manually push them through. If that makes sense.