Group Mail not working

Dear All
Kindly help in this we have installed nextcloud 19.0.2 on centos 8
first time and facing various issue

group mail alert of file folder sharing not working
[/details]

Nextcloud version (eg, 19.0.2):
Operating system and version (eg, Centos 08):
Apache or nginx version (eg, Apache 2.4.37):
PHP version (eg, 7.4):

The issue you are facing:

group mail not sent when share files in group
individual mail sent when select single user
Is this the first time you’ve seen this error? (Y/N):Y

The output of your Nextcloud log in Admin > Logging:

Warning	mail	not enough messages to train a classifier		2020-10-07T10:32:40+0530
Warning	mail	not enough messages to train a classifier		2020-10-07T10:25:02+0530
Warning	mail	KItinerary binary adapter is not available, can't extract information		2020-10-07T10:10:48+0530
Warning	mail	KItinerary binary adapter is not available, can't extract information		2020-10-07T10:10:45+0530

The output of your config.php file in /path/to/nextcloud (make sure you remove any identifiable information!):

PASTE HERE
```[root@localhost config]# cat config.php
<?php
$CONFIG = array (
  'instanceid' => 'ocxvxu4331lk',
  'passwordsalt' => 'CfvDNPFmpakvllv2SaFeqTn418OpAA',
  'secret' => 'uabWVNy6+2d3xogXY/GlXL2HaLCt87yCbzCRRr44VK7SYGxV',
  'trusted_domains' =>
  array (
    0 => '10.254.253.130',
  ),
  'datadirectory' => '/var/www/html/nextcloud/data',
  'dbtype' => 'mysql',
  'version' => '19.0.2.2',
  'overwrite.cli.url' => 'http://10.254.253.130',
  'dbname' => 'nchdbname',
  'dbhost' => 'localhost',
  'dbport' => '',
  'dbtableprefix' => 'oc_',
  'mysql.utf8mb4' => true,
  'dbuser' => 'kuser',
  'dbpassword' => 'xxxx',
  'installed' => true,
  'mail_from_address' => 'neeraj',
  'mail_smtpmode' => 'smtp',
  'mail_sendmailmode' => 'smtp',
  'mail_domain' => 'xyz.com',
  'mail_smtpauth' => 1,
  'mail_smtphost' => 'mail.domain.com',
  'mail_smtpport' => '25',
  'mail_smtpname' => 'mail@domain.in',
  'mail_smtppassword' => 'passwrd',
  'allow_local_remote_servers' => true,
  'memcache.local' => '\\OC\\Memcache\\APCu',
  'memcache.locking' => '\\OC\\Memcache\\Redis',
  'redis' =>
  array (
    'host' => 'localhost',
    'port' => 6379,
  ),
  'maintenance' => false,
#  'activity_expire_days' => 1,

);
[root@localhost config]#


kindly help in this any one it will be helpfull for us