Federation should be fixed now, just taking a bit to catch up on activities
Federation & pictrs were broken due to some dns issues. If you see an issue like that happening again best way to report it to the admins are in our discord or matrix (links are in https://me.programming.dev/)
if a larger community has no posts but it does on other instances its cause its hidden by default and you need to sub to it to see posts. Usually happens for political communities but full list of communities affected by that are in https://legal.programming.dev/docs/hidden-communities/)
applications are typically accepted instantly or within a couple hours
if not then it got denied because you didnt accept the TOS