Answer
GMS Secure Socket Layer has returned an error to the remote server’s VRFY command because GMS has been configured to only accept messages encrypted by the secure socket layer (SSL ) from this remote system. No communication between the remote server/client and GMS will be possible until the remote server correctly negotiates a secure connection. GMS uses the standard secure transport specified in RFC2487 to ensure compatibility with other messaging servers.
In this case, session Undefined is processing a connection from Undefined. The remote server gave the SMTP command
Undefined
GMS rejected the command with
530 Must issue a STARTTLS command first.
To resolve this problem, make sure that
- GMS has the correct certificate installed;
- the remote server or client conforms to the SSL or STARTTLS standard; and
- the remote server or client is correctly configured.
See Also:
- What are the benefits of protocol level encryption?
- How do I set up Secure SMTP (STARTTLS)?
- How do I contact the owner of a client?
- Can I provide secure access to email?
- How do alerts work?
- What is the SMTP MAIL clause?
- What is the SMTP VRFY clause?
- What is SMTP Response Code Theory?
- Which Type of SSL Certificate should I choose?
- How do I contact the owner of a remote server?
Keywords:STARTTLS SSL VRFY RFC2487 encryption security anti-snooping secure 8101