The SMTP server is refusing my connection attempts

3431

The SMTP server is rejecting my password/login

1524

Cannot send emails using Outlook

1916

Cannot send emails using Outlook Express

4920

Cannot send email using Eudora

321

Cannot send email using Mozilla Thunderbird

2371

Cannot send email using TheBat

172

I receive Unroutable address bounce back error message.

1167

Error: "Retry time not reached for any host"

1361

Error: "Too many recipients"

973

IP has been blacklisted by an antispam organization

374

Error: Invalid HELO

321

My mobile device cannot send mails

187

Which smtp port to use - 25 or 2525?

344

Error: Could not complete sender verify

302

Error 503: Valid RCPT command must precede DATA

2525

Error 553: Unable to verify address

784

Error: "The connection to the server was interrupted"

1080

What is the MTA retry timeout on your servers?

127

Cannot send attachments

920

I cannot send emails from my BlackBerry

180

Possible problems after migration to mini_sendmail on siteground servers

18