Password command failed: 535 Authentication Failed

I am using Zoho mail for my wordpress shopping site.
The SMTP was working properly before 1 month. but now I am unable to send email using Zoho SMTP.
Here is the SMTP details I am using
smtp.zoho.com
465 SSL
Please resolve the issue.
The SMTP debugging output is shown below:
2017-08-09 07:23:54	Connection: opening to ssl://smtp.zoho.com:465, timeout=300, options=array (
                   	                  )
2017-08-09 07:23:54	Connection: opened
2017-08-09 07:23:54	SMTP -> get_lines(): $data is ""
2017-08-09 07:23:54	SMTP -> get_lines(): $str is  "220 mx.zohomail.com SMTP Server ready August 9, 2017 12:23:54 AM PDT
                   	                  "
2017-08-09 07:23:54	SERVER -> CLIENT: 220 mx.zohomail.com SMTP Server ready August 9, 2017 12:23:54 AM PDT
2017-08-09 07:23:54	CLIENT -> SERVER: EHLO sandeepti.com
2017-08-09 07:23:54	SMTP -> get_lines(): $data is ""
2017-08-09 07:23:54	SMTP -> get_lines(): $str is  "250-mx.zohomail.com Hello sandeepti.com (cp-32.webhostbox.net (199.79.62.93))
                   	                  "
2017-08-09 07:23:54	SMTP -> get_lines(): $data is "250-mx.zohomail.com Hello sandeepti.com (cp-32.webhostbox.net (199.79.62.93))
                   	                  "
2017-08-09 07:23:54	SMTP -> get_lines(): $str is  "250-AUTH LOGIN PLAIN
                   	                  "
2017-08-09 07:23:54	SMTP -> get_lines(): $data is "250-mx.zohomail.com Hello sandeepti.com (cp-32.webhostbox.net (199.79.62.93))
                   	                  250-AUTH LOGIN PLAIN
                   	                  "
2017-08-09 07:23:54	SMTP -> get_lines(): $str is  "250 SIZE 53477376
                   	                  "
2017-08-09 07:23:54	SERVER -> CLIENT: 250-mx.zohomail.com Hello sandeepti.com (cp-32.webhostbox.net (199.79.62.93))
                   	                  250-AUTH LOGIN PLAIN
                   	                  250 SIZE 53477376
2017-08-09 07:23:54	Auth method requested: UNKNOWN
2017-08-09 07:23:54	Auth methods available on the server: LOGIN,PLAIN
2017-08-09 07:23:54	Auth method selected: LOGIN
2017-08-09 07:23:54	CLIENT -> SERVER: AUTH LOGIN
2017-08-09 07:23:54	SMTP -> get_lines(): $data is ""
2017-08-09 07:23:54	SMTP -> get_lines(): $str is  "334 VXNlcm5hbWU6
                   	                  "
2017-08-09 07:23:54	SERVER -> CLIENT: 334 VXNlcm5hbWU6
2017-08-09 07:23:54	CLIENT -> SERVER: Y2hpdHJhc2VucGFuZHJhQHNhbmRlZXB0aS5jb20=
2017-08-09 07:23:54	SMTP -> get_lines(): $data is ""
2017-08-09 07:23:54	SMTP -> get_lines(): $str is  "334 UGFzc3dvcmQ6
                   	                  "
2017-08-09 07:23:54	SERVER -> CLIENT: 334 UGFzc3dvcmQ6
2017-08-09 07:23:54	CLIENT -> SERVER: VGVzdEAwOTA5
2017-08-09 07:23:54	SMTP -> get_lines(): $data is ""
2017-08-09 07:23:54	SMTP -> get_lines(): $str is  "535 Authentication Failed
                   	                  "
2017-08-09 07:23:54	SERVER -> CLIENT: 535 Authentication Failed
2017-08-09 07:23:54	SMTP ERROR: Password command failed: 535 Authentication Failed
2017-08-09 07:23:54	SMTP Error: Could not authenticate.
2017-08-09 07:23:54	CLIENT -> SERVER: QUIT
2017-08-09 07:23:54	SMTP -> get_lines(): $data is ""
2017-08-09 07:23:54	SMTP -> get_lines(): $str is  "221 mx.zohomail.com closing connection
                   	                  "
2017-08-09 07:23:54	SERVER -> CLIENT: 221 mx.zohomail.com closing connection
2017-08-09 07:23:54	Connection: closed
2017-08-09 07:23:54	SMTP Error: Could not authenticate.