Mail App doest not synchronize email

[reynum2]

Steps to reproduce

1. having a free.fr mail box
2. install Mail App
3. Try to synchronize your mail box
   SMTP port 587
   IMAP port 993

Expected behaviour

My Email in inbox must be visible

Actual behaviour

Nothing is showed
But we can see if new messages are present.

Server configuration

Docker instance on Linux Debian 9
Apache 2.4.25
MariaDB 10.1.26
PHP 7.0.30
Nextcloud 14.0.1 Updated from an older Nextcloud 14.0.0

Login as admin user into your Nextcloud and access
http://example.com/index.php/settings/integrity/failed
No errors have been found.

Nextcloud configuration:

Config report

Insert your config.php content here.

$CONFIG = array (
  'instanceid' => '****',
  'passwordsalt' => '*****',
  'secret' => '******',
  'trusted_domains' =>
  array (
    0 => '127.0.0.1:5555',
    1 => 'nextcloud.reynum.eu',
  ),
  'datadirectory' => '/var/www/nextcloud/data',
  'dbtype' => 'mysql',
  'version' => '14.0.1.1',
  'overwrite.cli.url' => 'http://127.0.0.1:5555',
  'dbname' => 'nextcloud',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'dbuser' => 'reynum',
  'dbpassword' => '******',
  'installed' => true,
  'updater.secret' => '******',
  'maintenance' => false,
  'theme' => '',
  'loglevel' => 2,
);

Are you using encryption: no

Client configuration

Firefox 52.8.1 esr

Operating system:
No anormal logs in apache or linux

Nextcloud log (data/nextcloud.log)

{"reqId":"TFJcClVAywoLka5f0ASe","level":3,"time":"2018-10-03T14:01:03+00:00","remoteAddr":"212.129.63.134","user":"reynum","app":"PHP","method":"GET","url":"\/index.php\/apps\/mail\/api\/accounts\/1\/folders\/SU5CT1g%3D\/messages?filter=","message":"Undefined index: count at \/var\/www\/nextcloud\/apps\/mail\/vendor\/pear-pear.horde.org\/Horde_Imap_Client\/Horde\/Imap\/Client\/Socket.php#2551","userAgent":"Mozilla\/5.0 (X11; Linux x86_64; rv:52.0) Gecko\/20100101 Firefox\/52.0","version":"14.0.1.1"}

[nextcloud-bot]

GitMate.io thinks possibly related issues are #6325 (mail app does not send fqdn), #1596 (Mail app doe not send, shouldn't use "pilelining"), #1979 (Need a nice app icon for share by mail), #106 (Sharing broken when LDAP and Mail App is enabled), and #3032 (sharebymail app sends UID of LDAP user instead of their DisplayName / Email).

[rullzer]

Please submit this to the repository of the mail app http://github.com/nextcloud/mail