smtp Broken pipe issue with email.php

Hi there I am complete newbie here and desperately need some advice.

We have a crm and its stopped sending out emails from a cron job.

Error below: 

ERROR - 2019-09-16 00:00:10 --> Severity: Notice  --> fwrite() [<a href='function.fwrite'>function.fwrite</a>]: send of 3505 bytes failed with errno=32 Broken pipe /home/crmvoxsi/public_html/system/libraries/Email.php 1846


basically its not piping correctly.

here is line 1846: in BOLD BELOW

/**
* Send SMTP data
*
* @access protected
* @return bool
*/
protected function _send_data($data)
{
if ( ! fwrite($this->_smtp_connect, $data . $this->newline))
{
$this->_set_error_message('lang:email_smtp_data_failure', $data);
return FALSE;
}
else
{
return TRUE;
}
}


If you can advise i would be really grateful as its a big issue for us

thanks in advance.

Bo