This post describes an issue when trying to view classic publishing pages in SharePoint Online and how to resolve.

The issue
After migrating publishing sites from SharePoint 2010 – SharePoint Online, I encountered an issue with classic SharePoint Server publishing pages. Post-migration, some publishing pages wouldn’t open and displayed this error message:

Resolution
The Microsoft documentation on how to resolve this is pretty good, but I found it didn’t quite get me to fix my issue. Here’s what I did:
- Navigate to Site Content & Structure: /_layouts/sitemanager.aspx. NOTE: You need to be a SharePoint admin to access
- Open the Pages library > find your broken page > click on the drop-down button and press edit page settings

- Select the (Welcome Page) Blank Web Part Page layout

- Press OK
When I had to do this for my broken pages, there was a warning message above the page layout that said “Current page layout is not valid. Please select a valid page layout from the drop down list below”. I just selected the (Welcome Page) Blank Web Part Page layout anyway, pressed OK and it worked.