554 validating sender
Almost always, this means that the inbox either no longer exists, or that it never existed!
Please set your browser to accept cookies to continue.[Win32Exception (0x80004005): The network path was not found] [Sql Exception (0x80131904): A network-related or instance-specific error occurred while establishing a connection to SQL Server. Verify that the instance name is correct and that SQL Server is configured to allow remote connections. (provider: Named Pipes Provider, error: 40 - Could not open a connection to SQL Server)] System. SMTP Reply Code 503 is more often an indicator that the SMTP server you are trying to use requires authentication and you tried to send a message without authentication (username password).Check "Common settings" to verify authentication settings (mostly ESMTP authentication is used) for this server. 251 – The recipient is not local to the server, but the server will accept and forward the message.
The good news is that the SMTP error messages you need to worry about as an email sender are really primarily limited to just a few – those in the 5XX range – and of those, the ones that you really need to worry about are the ones in the 55X range – i.e. Of these, by far the most common one – the one that as a sender you will see most often and to which you must pay immediate attention – is the 550 SMTP error code, which can range from “user not found” to “mailbox unavailable” to any number of other similar variations, but which for you, dear mail sender, should almost always be read to mean “remove this email address from your mailing list immediately.” (On the other hand, your mail server administrator should care deeply about many more of these codes, however we assume that if they are administering your outbound mail server, they are already familiar with them.) So, back to that 550 error code.
Try Get Connection(Db Connection owning Object, Task Completion Source`1 retry, Db Connection Options user Options, Db Connection Internal& connection) 117 System.
Try Get Connection(Db Connection owning Connection, Task Completion Source`1 retry, Db Connection Options user Options, Db Connection Internal old Connection, Db Connection Internal& connection) 267 System.
If a SMTP client sends a SMTP command which h Mail Server considers beeing too long, h Mail Server issues this error.
This error typically indicates a client defect or a hacking attempt.
Description: An unhandled exception occurred during the execution of the current web request. Win32Exception: The network path was not found Source Error: An unhandled exception was generated during the execution of the current web request.