根据文档https://docs.iredmail.org/public.folder.html步骤操作，可以web页面并未显示公共文件夹PublicFloder。dovecot.log内容如下：
root@mail:/var/log/dovecot# tail dovecot.log
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: maildir++: root=/var/vmail/public, index=, indexpvt=/var/vmail/vmail1/kingcooler-sz.com.cn/t/e/s/test-2017.12.12.15.58.25//Maildir/public, control=/var/vmail/vmail1/kingcooler-sz.com.cn/t/e/s/test-2017.12.12.15.58.25//Maildir/public, inbox=, alt=
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl: initializing backend with data: vfile
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl: acl username = test@kingcooler-sz.com.cn
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl: owner = 0
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl vfile: Global ACLs disabled
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl vfile: file /var/vmail/vmail1/kingcooler-sz.com.cn/t/e/s/test-2017.12.12.15.58.25//Maildir/.Drafts/dovecot-acl not found
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl vfile: file /var/vmail/vmail1/kingcooler-sz.com.cn/t/e/s/test-2017.12.12.15.58.25//Maildir/.Sent/dovecot-acl not found
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl vfile: file /var/vmail/vmail1/kingcooler-sz.com.cn/t/e/s/test-2017.12.12.15.58.25//Maildir/.Junk/dovecot-acl not found
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl vfile: file /var/vmail/vmail1/kingcooler-sz.com.cn/t/e/s/test-2017.12.12.15.58.25//Maildir/.Trash/dovecot-acl not found
Dec 18 16:54:23 mail dovecot: imap(test@kingcooler-sz.com.cn): Debug: acl vfile: file /var/vmail/vmail1/kingcooler-sz.com.cn/t/e/s/test-2017.12.12.15.58.25//Maildir/dovecot-acl not found
root@mail:/var/log/dovecot#
张老大，帮忙看看哪里问题。