Early in our migration to Office 365, we decided to use the free public site provided with Sharepoint Online as a place to set up our on-boarding process for new users. We like the features of Sharepoint for documents and forms, and it is extremely simple to use, without needing to set up yet another set of passwords.
The only issue was that by default, anonymous users could not access a lot of the Sharepoint content. Luckily, someone created an install WSP solution to turn this anonymous access on, and we have since become dependent on it. Office 365 no longer includes this public site functionality for new customers, but we are grandfathered in.
Sharepoint Online's most recent update broke the ability on public sites for anonymous users or guests to access a document library without being logged in. The symptoms may include a blank document library, or a redirection to a broken URL (in my experience, Sharepoint tried to redirect the link to the login page but removed the domain component of the URL. This may have been caused by the Anonymous Access WSP solution). In some cases, the redirect took a few seconds, so waiting on the page triggered the error message, but clicking quickly on a document would load it correctly.
The workaround is simple: simply create a new page and add an App Part that displays the document library's contents. Then update the link to point to the new page.
- Visit your Public Site, and login.
- Go to the gear icon, and select "Site Contents"
- Click on Pages, and then Add a new Page
- Next, Edit the Page and Insert a new App Part
- Select the Document Library (or other content) that you were not able to display directly.
- Next, you may want to update the view so that all documents are displayed, instead of a summary. Click on the newly inserted App Part, on the Ribbon select Web Part, and then Properties. Change the view to the one that you prefer.