I got this error because I worked locally, uploaded my templates to the server but did not import my local db to the remote db since I work with a team and needed to preserve the online, active db.
Therefore, I needed to recreate fields, sections, entries, and plugin settings on the server CMS, but I forgot to change the sectionId hidden in my template to reflect what the new channel's section ID was. On my local it was 13, but when I created it on the server, it was 12 and I just needed to change it in the code in the from like so:
<input type="hidden" name="sectionId" value="12">
Hope that helps someone out there.