Error sending e-mail. The SMTP server requires a secure connection or the client was not authenticated. The server response was: Authentication requir

System.Net.Mail.SmtpException: The SMTP server requires a secure connection or the client was not authenticated. The server response was: Authentication required at System.Net.Mail.MailCommand.CheckResponse(SmtpStatusCode statusCode, String response) at System.Net.Mail.MailCommand.Send(SmtpConnection conn, Byte[] command, MailAddress from, Boolean allowUnicode) at System.Net.Mail.SmtpTransport.SendMail(MailAddress sender, MailAddressCollection recipients, String deliveryNotify, Boolean allowUnicode, SmtpFailedRecipientException& exception) at System.Net.Mail.SmtpClient.Send(MailMessage message) at Nop.Services.Messages.EmailSender.SendEmail(EmailAccount emailAccount, String subject, String body, MailAddress from, MailAddress to, IEnumerable`1 bcc, IEnumerable`1 cc) at Nop.Services.Messages.EmailSender.SendEmail(EmailAccount emailAccount, String subject, String body, String fromAddress, String fromName, String toAddress, String toName, IEnumerable`1 bcc, IEnumerable`1 cc) at Nop.Services.Messages.QueuedMessagesSendTask.Execute()

Complete shot in the dark, here, but try setting your port to 587 if it is not already.

This is the log error when I try to do payment through paypal (sanbox) . I get Pimp RC: 3514 in paypal and I have uploaded my website online.

This is the log error when I try to do payment through paypal (sanbox) . I get Pimp RC: 3514 in paypal and I have uploaded my website online.

This sounds like something you might want to read.

Sounds about right with Paypal. They are did some MASSIVE changes from a couple years ago, and I couldn't make sense of it when I was doing integration with them... big reason why I'm here using NopCommerce, because it had Authorize.Net ready to go.