No attachments working after 3.4.8 to 4.1 upgrade

[homeofeconomy]

After upgrading our 3.4 installation to 4.1, file attachments to posts return a "page cannot be displayed" error.  The old "uploads" directory was copied into the fresh 4.1 install folder before running the upgrade.  All background tasks have run a couple of times with no effect on this problem.  Does anyone have any thoughts?

[Anton K.]

Bump!