"no valid OpenPGP data found" when adding repository

Hi.

I've got a question about package authentication.
I recently created a ppa on launchpad : https://launchpad.net/~aff3ct/+archive/ubuntu/aff3ct.
But when I add this repository on ubuntu, I have a message "no valid OpenPGP data found.".
Full output : https://pastebin.com/u22Ru6UJ.
Then, this package remains unauthenticated until I add the key manually :
`sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys 45B56700`

How can the key be added automatically ?

Thanks.