SMTP Error: Authentication failure: SMTP server does not support authentication

[madcreativebg]

Hello,

I get the error when trying to send mail:

[27-Dec-2019 00:16:41 +0200]: SMTP Error: Authentication failure: SMTP server does not support authentication (Code: ) in /usr/share/nginx/html/webmail/program/lib/Roundcube/rcube.php on line 1689 (POST /webmail/?_task=mail&_unlock=loading1577398601567&_framed=1&_lang=bg&_action=send)

when using Roundcube 1.4.1. With Roundcube 1.3.10 on the same server and settings there is no problem.

[alecpl]

Some config defaults changed in 1.4. See #7011. Because smtp_pass/smtp_user is now set and your server does not allow authentication over insecure channel, you have to either disable authentication (clearing smtp_pass/smtp_user) or add tls:// prefix to smtp_server.

[johnnyutahh]

... you have to either disable authentication (clearing smtp_pass/smtp_user)...

For me, "clearing" the variables means the following (assigning said variables to null does not seem to work in my Roundcube 1.4.3 rig):

$config['smtp_user'] = '';
$config['smtp_pass'] = '';

(This might be obvious to most Roundcube admins, but I'm a newbie.)

[trasherdk]

It could also mean to comment out those 2 lines. Did you try that?

[johnnyutahh]

Thanks. I just did. Commenting out the above lines in /etc/roundcube/config.inc.php does not work. (The SMTP auth fails when attempting to send an email.) Setting the variables = '' (an empty string) seems to be the only way to do make an SMTP-server-with-no-auth work (to send an email).

So there seems to be 3 different ways one can interpret "clearing" a variable, depending on the context:

1. set variable to empty string
2. set variable to null
3. comment out the variable (although said variable could be defined in another area)

If there's enough confusion in the Roundcube community about this, would it be helpful to clarify things surrounding "clearing a variable"?

[RichyT]

I have an SMTP server with no auth for the local subnet. I came here because although I unclicked "Use the current IMAP username and password for SMTP authentication", it wasn't clear that I had to delete the %u and %p to not use them and I was getting SMTP auth failures. Not to step on toes but I would suggest this could be cleaned up a little as it's a bit ambiguous.

(Edit: To be clear, it's all working fine now though 👍)

[GwynethLlewelyn]

Piping in late on a two-year-old closed thread, but since I have also encountered the same error, I'd like just to add my .02 ...

Under PHP 7.4/Roundcube 1.4.3, 'clearing' those variables really means:

$config['smtp_user'] = '';
$config['smtp_pass'] = '';

Setting them to null will not work.

Under Ubuntu 20.04, Roundcube will be installed with at least a defaults.inc.php which gets loaded before config.inc.php (as it should be). So, skipping those two settings will not work, since defaults.inc.php has the following settings:

$config['smtp_user'] = '%u';
$config['smtp_pass'] = '%p';

So these two configuration variables must be explicitly overwritten in config.inc.php with the empty string '', or else SMTP will refuse to authenticate.

Of course, some Roundcube configurations may be even more convoluted and include several other configuration files beyond these. Actually, I had a few of those around, which I thought weren't being included, but, to be on the safe side, I backed them up and deleted them — just keeping defaults.inc.php around, since it's expectable that it will be overwritten with sensible defaults when Roundcube 1.4.4 ships. In other words, if the only configuration file you have is defaults.inc.php, do not touch it, but keep it intact, and just override what you wish/need on config.inc.php. I believe that at least those two are guaranteed to work, but it's possible that some configurations only ship with defaults.inc.php (and you need to add your own config.inc.php) or possible just config.inc.php, filled in with all possible configuration values, which you may change — until the next Roundcube version comes around and wipes it clean...

An extra 👍 on the request for documenting this properly! After all, it might just require an extra comment line on defaults.inc.php... as @johnnyutahh so well mentioned, there are at least 3 ways to interpret 'clearing', according to context (i.e. each configuration variable may be 'cleared' differently...).

[Goe66els]

... you have to either disable authentication (clearing smtp_pass/smtp_user)...

For me, "clearing" the variables means the following (assigning said variables to null does not seem to work in my Roundcube 1.4.3 rig):

$config['smtp_user'] = '';
$config['smtp_pass'] = '';

(This might be obvious to most Roundcube admins, but I'm a newbie.)

А ларчик просто открывался, 3 дня гугления проб и ошибок... Чувак ты сделал мой день. Спасибо!!!!!

thank you dear friend you made my day !!!

[trasherdk]

After a new installation Roundcube Webmail 1.6.5, 3 years later, I got bitten by this thing, again 😢

$config['smtp_user'] = '';
$config['smtp_pass'] = '';

Overriding the default fixes that problem.

[ETNyx]

Same error, fix suggested in first response works too,...

// default.inc.php
$config['smtp_server'] = 'localhost';
// config.inc.php
$config['smtp_server'] = 'tls://localhost';