Error while sending mail using SQL server

The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 6 (2017-09-07T14:01:30). Exception Message: Cannot send mails to mail server. (Service not available, closing transmission channel. The server response was: Cannot connect to SMTP server 204.11.56.48 (204.11.56.48:25), connect error 10060).
)

			EXECUTE msdb.dbo.sysmail_add_account_sp
@account_name = 'MailTest',
@description = 'Sent Mail using SQL Server',
@email_address = 'imran@execsql.org',
@display_name = 'SQL Server-Mail Send',
@username='imran@execsql.org',
@password='your_password',
@mailserver_name = 'your_email_server_name'

--delete from sysmail_account
--select * from sysmail_account

EXECUTE msdb.dbo.sysmail_add_profile_sp
@profile_name = 'MailTest',
@description = 'Profile used to send mail'

--select * from sysmail_profile

EXECUTE msdb.dbo.sysmail_add_profileaccount_sp
@profile_name = 'MailTest',
@account_name = 'MailTest',
@sequence_number = 1

--select * from sysmail_profileaccount

EXECUTE msdb.dbo.sysmail_add_principalprofile_sp 
@profile_name = 'MailTest', 
@principal_name = 'public', 
@is_default = 1 ;




exec msdb.dbo.sp_send_dbmail 
@profile_name = 'MailTest', 
@recipients = 'paulvinayak70@gmail.com', 
@subject = 'Mail Test', 
@body = 'Mail Sent Successfully', 
@body_format = 'text'



but it gives error 
when I execute view 

select * from sysmail_allitems
at column send_status   it gives values as Failed


and description of error is as

The mail could not be sent to the recipients because of the mail server failure. (Sending Mail using Account 4 (2017-09-07T12:17:46). Exception Message: Cannot send mails to mail server. (Service not available, closing transmission channel. The server response was: Cannot connect to SMTP server 204.11.56.48 (204.11.56.48:25), connect error 10060).
)