Notification LED on Nexus 5 (Hammerhead)

After 6 months testing I finally made a move from Sailfish to /e/ on my Hammerhead.
There is one setting I can not find.
After receiving an e-mail (standard /e/ app) I do get an notification on the screen, but affer the screen blanks there will be no notification by means of the LED. I did try to change settings by adding the mail app as an extra notification in the notification manager. No succes.
Anyone an idea?