Zepto Mail SMTP closing connection Sending invoice with PDF Attachment

Zepto Mail SMTP closing connection Sending invoice with PDF Attachment

Hi, I'm having problem with the smtp for transaction mail using zoho as smtp server.
The file containing PDF File. Please help.. Thank you
Log as follow:

++ Starting Swift_SmtpTransport
<< 220 mx.zohomail.com SMTP Server ready June 15, 2022 11:42:56 PM PDT
>> EHLO myemail
<< 250-mx.zohomail.com Hello <myemail@domain.com> (server.xxx.com (serverip))
250-AUTH LOGIN PLAIN 250 SIZE 53477376
>> AUTH LOGIN
<< 334 VXNlcm5hbWU6
>> ZW1haWxhcHBzbXRwLmE5NmJmZTk1ZjM5MzI2Nw==
<< 334 UGFzc3dvcmQ6
>> NUROMUY0R3hxOTNIX19kZmMyOTRjM2YxMmY=
<< 235 Authentication Successful
++ Swift_SmtpTransport started
>> MAIL FROM:<crm@vimobe.com>
<< 250 Sender <myemail@domain.com> OK

>> RCPT TO:<myemail@domain.com>

<< 250 Recipient <myemail@domain.com> OK
>> DATA
<< 354 Ok Send data ending with <CRLF>.<CRLF>
>> .
<< 250 Message received
Sending and email with Test Invoice Attachment.... ++ Stopping Swift_SmtpTransport
>> QUIT
<< 221 mx.zohomail.com closing connection
++ Swift_SmtpTransport stopped