==== REQUIRED BASIC INFO OF YOUR IREDMAIL SERVER ====
- iRedMail version (check /etc/iredmail-release): 0.9.9 MYSQL edition
- Deployed with iRedMail Easy or the downloadable installer? IRedmailEasy
- Linux/BSD distribution name and version: Ubuntu 18.04.1 LTS
- Store mail accounts in which backend (LDAP/MySQL/PGSQL):Mysql
- Web server (Apache or Nginx):Nginx
- Manage mail accounts with iRedAdmin-Pro? No
- [IMPORTANT] Related original log or error message is required if you're experiencing an issue.

====
Hello
I have a problem with the server
None of the users can pick up the mail. E-mail programs display a message: TLS connection cannot be established.

There is information in dovecot logs: "pop3-login: Disconnected (tried to use disallowed plaintext auth): user=<test@domain.com>", and "dovecot: auth: Error: read(anvil-auth-penalty) failed: EOF" , "dovecot: auth: Error: net_connect_unix(anvil-auth-penalty) failed: Permission denied
"
I'd be grateful for your help in solving the problem