[asp.net] Mailbox unavailable. The server response was: 5.7.1 Unable to relay for [email protected]

I was facing the identical problem and followed the (very clearly spelled out) steps in Vinod's reply, however this then created a different error:

Unable to read data from the transport connection: net_io_connectionclosed

I did a bit more digging and poking around and (while I'm not sure why this worked) I solved it by:
- Going back into IIS6.0 management console
- Open SMTP Virtual Server properties
- On General tab, changing the 'IP Address:' setting back to '(All Unassigned)'

Not sure why this works, but hopefully will help out someone facing the same problem in the future.

Examples related to asp.net

RegisterStartupScript from code behind not working when Update Panel is used You must add a reference to assembly 'netstandard, Version=2.0.0.0 No authenticationScheme was specified, and there was no DefaultChallengeScheme found with default authentification and custom authorization How to use log4net in Asp.net core 2.0 Visual Studio 2017 error: Unable to start program, An operation is not legal in the current state How to create roles in ASP.NET Core and assign them to users? How to handle Uncaught (in promise) DOMException: The play() request was interrupted by a call to pause() ASP.NET Core Web API Authentication Could not load file or assembly 'CrystalDecisions.ReportAppServer.CommLayer, Version=13.0.2000.0 WebForms UnobtrusiveValidationMode requires a ScriptResourceMapping for jquery

Examples related to email

Monitoring the Full Disclosure mailinglist require(vendor/autoload.php): failed to open stream Failed to authenticate on SMTP server error using gmail Expected response code 220 but got code "", with message "" in Laravel How to to send mail using gmail in Laravel? Laravel Mail::send() sending to multiple to or bcc addresses Getting "The remote certificate is invalid according to the validation procedure" when SMTP server has a valid certificate How to validate an e-mail address in swift? PHP mail function doesn't complete sending of e-mail How to validate email id in angularJs using ng-pattern

Examples related to iis-7

Accessing a local website from another computer inside the local network in IIS 7 500.21 Bad module "ManagedPipelineHandler" in its module list HTTP Error 503. The service is unavailable. App pool stops on accessing website IIS - 401.3 - Unauthorized 500.19 - Internal Server Error - The requested page cannot be accessed because the related configuration data for the page is invalid ASP.NET Web API application gives 404 when deployed at IIS 7 WebApi's {"message":"an error has occurred"} on IIS7, not in IIS Express enabling cross-origin resource sharing on IIS7 How to fix 'Microsoft Excel cannot open or save any more documents' IIS 7, HttpHandler and HTTP Error 500.21

Examples related to iis-6

How to allow download of .json file with ASP.NET IIS Request Timeout on long ASP.NET operation Mailbox unavailable. The server response was: 5.7.1 Unable to relay for [email protected] Login failed for user 'DOMAIN\MACHINENAME$' Socket transport "ssl" in PHP not enabled What causes an HTTP 405 "invalid method (HTTP verb)" error when POSTing a form to PHP on IIS? How to redirect a URL path in IIS? What does 'IISReset' do?