[Exim] SSL/TLS

Hello

Safety I use exim 3.35 etje would like to activate the support ssl

So my file of configuration I put

tls_advertise_hosts = *
tls_certificate = /etc/mail/certs/cert.pem

Nevertheless I have errors in my logs

2002-12-17 18:00:45 TLS error on connection from nan-smtp-12.noos.net
(smtp.noos.fr) [212.198.2.83] (SSL_CTX_use_certificate_file):
error:0200100D:system library:fopen:Permission denied

Is what you know what I forgot?

Later