[AUTH] Plaintext authentication disallowed on non-secure (SSL/TLS) connections.

Hello i am trying to read my somename@superhost.gr via GMail so to have both Gmail and domain mail together.
But when GMail tries to read that mail it gives me as output:

'Server returned error: “[AUTH] Plaintext authentication disallowed on non-secure (SSL/TLS) connections.”

What is the exact steps i need to take in order to be able to read my domain’s mail through GMail?

I use Virtualmin and in Dovecot i have set “Disallow plaintext authentication in non-SSL mode” to NO, for not blocking it, so i dont understand why iam getting this error.

And even better could you tell me tha exact steps i need to take to enable SSL or STARTTLS in Virtualmin’s Dovecot?
Thank you.

I have gone to VirtualMin Lets Encrypt created a certificate BUT when i try to apply it to Dovecot i get:

Copying certificate and key to Dovecot files …
… wrote out certificate and CA in /etc/pki/dovecot/certs/dovecot.pem, and key in /etc/pki/dovecot/private/dovecot.pem
Enabling SSL in Dovecot configuration …
… done

Please help.

Please try to read some docs on the web, wiki dovecot, postfix and so.

If using ssl then ofcourse it is / should not be possible to use plain text in nonssl /tls , otherwiser secure ssl connections makes no sense at all, if still allowing those insecure plain text.

I don’tr know which versions but there is/was a bug with that copy dovecot cert.

Also take a look if using hostname / mainserver cert or your domain/virtualserver cert ( SNI then if more on 1 IP) both for postfix not supporting that for dovecot ( emailclients part) it is possible but can cost some extra work and reading / configuration.

( docs/wiki here on virtualmin with latest … i can’t find myself some is on the forum , but hard to understand)

Could you please tell me how to enable SSL for Dovecot so i can read my domain mail through GMail?

I have gone to VirtualMin Lets Encrypt created a certificate BUT when i try to apply it to Dovecot i get:

Copying certificate and key to Dovecot files … … wrote out certificate and CA in /etc/pki/dovecot/certs/dovecot.pem, and key in /etc/pki/dovecot/private/dovecot.pem Enabling SSL in Dovecot configuration … … done

Nut when i look at the services Dovecot although it says above that it wrote the certificate to file it actually didnt wrote it and its like i never applied it.

Please give me detailed help as iam unexperiended with this.

It sounds like the real issue here is that the automatically renewed Let’s Encrypt cert doesn’t get copied to my Usermin and Dovecot only to other 3 services.

Can’t help while i’m doing configs in CLI , parts/ly not supported in virtualmin GUI, and not using common settings i believe. ( also ofcourse i don’t use such as gmail and co respecting my privacy and from others we are mailing with to much to use such… )

So then i bring you more off track regarding supported virtualmin configs.

Advice read docs / wiki on official site dovecot / postfix .
Virtualmin you can book training see this forum, or support tickets, but both makes more sense if you did some reading before yourself, and writing down the questions you have.

Is this the certificate we are talking about?

[root@superhost ~]# ll /home/nikos/ssl*

-rwxr-x— 1 nikos nikos 1653 Nov 4 18:55 /home/nikos/ssl.ca

-rwx------ 1 nikos nikos 1996 Nov 4 15:14 /home/nikos/ssl.cert

-rwx------ 1 nikos nikos 1997 Nov 4 18:53 /home/nikos/ssl.combined

-rwx------ 1 nikos nikos 3677 Nov 4 18:53 /home/nikos/ssl.everything

rwx------ 1 nikos nikos 1679 Nov 4 15:14 /home/nikos/ssl.key

Please just tell me how to manually copy the above certification in Dovecot. I am loggen in via SSH to my server as root and i have some linux experience.
Please tell me the cli commands i have to give.

I’m only using mainserver cert ( hostname) for all virtualservers /domains then path to those cert in dovecot config is only thing you have to set, all other you have to comment out # / delete then ( in the dovecot config file , i mean not the certs ofcourse) BACKUPS!

Sorry but GUI i don’t use for dovecot and postfix while some…

mx record for all is then ofcourse pointing to mainserver/hostname. ( so are the mailclients)

I dont understand.

  1. What file is the cert? /home/nikos/ssl.cert or something else?
  2. If the above is True, what is the command to use to manually copy the certification to Dovecot server?

Please explain to me as it is essential for me to be able to read my superhost.gr mail through GMail and for that as far as i understand i need to find the cert file and copy it to Dovecot.

Please be thorough
Thank you in advance.

Depending on versions


can’t help while not using gmail at all!

i cannot understand it, isnt it just there a copy command to do it?

If using cli and manual doing config settings you have to know what you do and also knowing the product you’re doing that for, otherwise it could be a “fatal” config without even knowing such.

BACKUPS, and testing are important.

You have to know your names, paths and ips ( v4 and v6) used and what you’want to achiev before touching.

CLI manual config files editing is not copy … , GUI is fill in and set some if supported in Control panel.

I did write not using that GUI so can’t help also can’t teach… CLI doing manual configurations for apps

i know that things. ALL I NEED TO DO IS



No sorry while i don’t know other configs of virtualmin then the one i am using, that is sofar i can see not what you need.

I did however write above about bug for that part, here on the forum somewhere you have to use search or websearch one or more guys did post how they managed… i don’t know where and i didn’t write that topic …

I found this after searching the forum.

Submitted by chill_Surf on Tue, 10/15/2019
The bug is back again.
I tried to do a fresh install on a new CentOS 7 system, after install of CentOS I updated the system and then I installed Virtualmin. After the installation I created a server and a Let’s Encrypt certificate for it.
I Copied the certificates to webmin,virtualmin,postfix, dovecot but then i noticed that the “Copy to Dovecot” button was still there.

This post has been unanswered and i have the EXACT SAME PROBLEM. COULD SOMEBODY HELP ME PLEASE?