When you trying to publish an InfoPath form to document library for the first time it successes.
But try again; you will get the following error message
“InfoPath failed to publish because the default content type in the document library is not based on the Form content type.”
- Go to Site Actions >> Site Settings >> Manage site features
Activate the feature “Team Collaboration Lists”
In InfoPath form; File >> Publish >> SharePoint Server
Publish the form again to a new document library instead of the old one because the old one was create of template Document Library
And the correct on should be Form Library