Issues concerning email sending are unfortunately pretty common, either in daily communications or when it comes to newsletters and bulk messages.
So, why is it that sometimes your mail client is not sending emails? Maybe it keeps on receiving them, but the outgoing emails are not sent at all. What is happening?
Provided that you’re correctly connected to the internet (yes, it happens.), the causes are probably related to your SMTP server – the machine that takes care to deliver your outcoming messages.
In fact, the normal servers associated to a common email provider (like Gmail or Hotmail) can run into several problems as they are not monitored: the best choice to avoid them all is to rely on a professional outgoing server.
That said, here are the most frequent “email not sending” issues, and how to troubleshoot them:
The email authentication failed. If you’re using SMTP authentication like SSL, check again your username and password.
There’s a port problem. SMTP normally uses port 25 but it may happen to be blocked by your ISP: try switch to port 587 (or port 465 if you’re connecting via SSL).
The SMTP settings are mistaken. Maybe you configured your mail client with the wrong outgoing server name
Firewall or antivirus issues. Make sure that you have an exception rule for your SMTP service in your firewall, proxy service or antivirus settings.
If the client keeps not sending emails, it’s likely that you have a general issue with your Internet Service Provider (which you should contact immediately).
