We have a public-facing SharePoint 2010 Enterprise server hosting a Publishing Portal site running InfoPath Forms Services. We have an InfoPath Form on the server which submits to a Form Library. This works fine for logged on users, but doesn't work for anonymous access users; they can view the Form but can't submit it.
So far we have:
- Checked that Anonymous User Access is enabled on both the Farm and SiteCollection.
- Disabled Lockdown Mode.
- Changed the permissions policies of the Web Application to remove "No Write" for Anonymous Access.
- Broken inheritance and set the permissions of the Form Library so that Anonymous User Access can View (the options for them to Add, Edit and Delete were greyed out).
- Tried this hack to allow us to set the permissions so that Anonymous User Access can Add to the Form Library.
- Tried creating it as an InfoPath Library Form and publish it as a content type instead as described in another answer on this site.
Using Fiddler to sniff the http traffic we can see that the POST to /_layouts/Postback.FormServer.aspx is working OK (getting a 200 response).
We are however getting a message appear in the browser saying "The form cannot be submitted to the specified SharePoint list or document library. The SharePoint location may be read-only or you may not have permissions to access it."
We have seen a few possible solutions which suggest using custom .NET code to perform the submit either by running with elevated privileges or as a submission via a web service, but we are hoping to avoid that extra work.
What are we doing wrong? Any help greatly appreciated.