AE doesn't recognise alpha channel in ProRes 4444 from FCP X

For my workflow I have to export a separate file for all the graphics from FCP X. I do this via Share Masterfile... and select ProRes 4444 and make a multitrack QuickTime movie. When I export this file, After Effects doesn't see the alpha channel. The weird thing is that the first few times it worked, but now it doesn't anymore. When I open the file in FCP X there is an alpha channel.

What am I doing wrong?

Try looking at the "interpret footage" menu inside ae under the matte options

www.premiumbeat.com/blog/interpret-footage-in-after-effects/