Android File Transfer/Mac - mp4 files are greyed out - S8

[mitkroy]

Samsung Galaxy S8 - I'm trying to transfer files from my phone to my Mac.
It was working fine yesterday with Android File Transfer, but now the files look greyed out and when I try to drag them across I get an error message.
I've tried: switching developer mode on, setting Default USB Configuration to 'Transferring Files.'

 

[mustang7757]

Have you tried another cable?