Auto-align and auto-blend grayed out

Hi,

I encounter an issue with Photoshop that always has worked for me in the past.  I want to focus stack several images but the auto-align and auto blend features are grayed out. Here's what I do:

1. from LR, I select 5 images (same image with different focus in the image)

2. right click and select: edit in -> open as layers in Photoshop

3. In Photoshop: select all layers

4. Edit -> Auto-Align layers (but can't select it because it's grayed out).

Any ideas what I'm doing wrong?

Thank you,

Pascal