Here is test email attempt log:
sasl.smtp.pobox.com = 208.72.237.25
220 a-sasl-quonix.sasl.smtp.pobox.com ESMTP Postfix
EHLO TThrottle_Mail
PIPELINING
SIZE
ETRN
STARTTLS
AUTH
AUTH=LOGIN
ENHANCEDSTATUSCODES
8BITMIME
STARTTLS
220 2.0.0 Ready to start TLS
AUTH LOGIN
503 5.5.1 Error: send HELO/EHLO first
QUIT
Server login failed. Username or password invalid.
sasl.smtp.pobox.com = 208.72.237.25
220 a-sasl-quonix.sasl.smtp.pobox.com ESMTP Postfix
EHLO TThrottle_Mail
PIPELINING
SIZE
ETRN
STARTTLS
AUTH
AUTH=LOGIN
ENHANCEDSTATUSCODES
8BITMIME
STARTTLS
220 2.0.0 Ready to start TLS
AUTH LOGIN
503 5.5.1 Error: send HELO/EHLO first
QUIT
Server login failed. Username or password invalid.