In case you haven't already tried it, you could try to reset the app by closing and opening it, check your connection speed, log out/ log in, the usual troubleshoot stuff. There was an issue about that earlier this year and seem to be the quickest fix for it.
If the issue is a shadowban though, then it may take up to 2 weeks before you can post again. Delete any potential content you have which may potentially be flagged as offensive. Alternatively, you're gonna want to use a different account from here on out.