Mail notification doesn't work anymore upgrade 8.12.7


I updated my system (centos 7) and gitlab Omnibus package to 8.12.7
email notification doesn’t work anymore for users .
sending mail from shell does works fine
I tried to set
gitlab_rails[‘smtp_enable’] = true
and other smtp settings in /etc/gitlab/gitlab.rb (the reconfigure/ restart) , no way :frowning:
is it nececesary to set those smtp parameters ?
is there a bug or am I missconfiguring my gitlab instance ?

I googled related topics , but no succes neither

regards .