SMTP Error: 0x800ccc6f. The server response was 554 5.7.1 PB error

The error indicates the PB error which comes only when the server detects some kind of mail spoofing attempt from the sender in simple words if the server is hosting a domain and someone else is sending the mails with the same domain but not using the smtp of the server it would be treated as a spoofing attempt and hence the server rejects it.

Their are two ways to solve this :

1) You use our SMTP in your dotnet application with the authentication and it would work.
2) if you want to use your own smtp then let us know the fixed IP of your smtp service and we’ll whitelist this IP on our server so that you may start getting mails from this IP.

We take a very dim view of SPAM. It is one of the most annoying things encountered on the Internet. Any client found to be spamming will have his/her account terminated immediately – no questions asked (we will investigate the report thoroughly before terminating any account). There is no warning or second chance. If we find that you have violated our Acceptable Usage Policy, we will report you and the incident to the proper local, state and federal authorities and will prosecute you to the full extent of the law.

SMTP

1. My web site incorporates some automated email scripts to communicate with users of my web site. Does my web site have access to an SMTP server that will allow relaying?

If you are using smtp server as your web server like ‘localhost’ then didn’t require any authentication OR user name + password to relay mails and if you use to relay mails from the mail server then you have to require authentication to relay mails due to mail server performance and we can easily find out who are sending spam or using more resources of mail server through the website script.

2. If so, does that server require authentication?

If you use mail server to relay mail like smtp server as mail.domainname.com then you have to require the emailid + password of the domain which you are using in the script to authentication and if you use localhost means webserver SMTP then you did’t require any authentication for it.

3. If so, what is the name or address of that SMTP server?

Address of the smtp server in both case are :

From the webserver smtp then you have to use smtp server as ‘localhost’ or server IP and in this case didn’t require authentication.

From the mail server then you have to use smtp server as mail.domainname.com or your mail server IP and in this case you have to require emailid + password to authentication on the mail server.

5. And what username and password combination should I use to authenticate with that SMTP server for email generated by my web site?

The any emailid + password of the domain which is you used in the smtp server variable in the send mail script.

6. Are there any other restrictions on the SMTP service or security requirements that I should be aware of?

No.. their is no other restriction for it because if we allow user to send mail without authentication through the script then your mail server performance also effected.