permission danied

Please elaborate more, on what you wanted to do and where you received the permission denied?
 
Are you on the newest version of the PMG? pmgversion -v
 
root@prox:/etc/letsencrypt/live/# pmgversion -v
proxmox-mailgateway: 5.0-7 (API: 5.0-53/ab040328, running kernel: 4.13.13-5-pve)
pmg-api: 5.0-53
pmg-gui: 1.0-30
proxmox-spamassassin: 3.4.1-54
proxmox-widget-toolkit: 1.0-9
pve-kernel-4.13.13-5-pve: 4.13.13-37
libpve-http-server-perl: 2.0-8
lvm2: 2.02.168-2
pve-firmware: 2.0-3
libpve-common-perl: 5.0-27
pmg-docs: 5.0-11
pve-xtermjs: 1.0-2
libarchive-perl: 3.2.1-1
libxdgmime-perl: 0.01-3
zfsutils-linux: 0.7.3-pve1~bpo9
libpve-apiclient-perl: 2.0-2