Internet or Network connection missing
Internet or network connection failures keep your e-mail program from sending and receiving messages. Verify that your computer can connect to the Internet or network.
Issues with Internet or Network e-mail server
Make sure that your Internet e-mail server or your Network e-mail server is not encountering issues by contacting either your Internet Service Provider or your Network administrator. They should be able to tell you if there are any e-mail server issues on their end that are preventing you from receiving or sending an e-mail.
E-mail program incorrectly configured
Many e-mail related problems are because of improperly configured mail settings. Verify that your e-mail program is properly configured to connect to your Internet or Network e-mail server. It is very common for the e-mail program to have either the incorrect POP or SMTP address.
As mentioned on the above links to POP and SMTP, the POP server is used to retrieve mail and the SMTP server is used to send mail. Therefore, if you are having difficulties receiving e-mail, verify that the correct POP server and port is defined. If you are unable to send mail, verify that the correct SMTP server and port is defined.
The default SMTP server is port 587, and the POP3 server is port 110. However, the actual POP3 and SMTP server name varies depending upon your Internet e-mail or Network e-mail provider. Usually it will be mail.[YOUR-DOMAIN-NAME.COM].
Note: Users may be unable to send an e-mail through an ISP other than their own due to SMTP restrictions that try to reduce spam on the ISP's network.
If you use a different Internet or Network connection while sending e-mail and are unable to send e-mail, verify with the ISP or Network Administrator that an SMTP block is not in place.
When a SMTP block is in place, you will receive one of the below errors.
- SMTP error
- SMTP rejected
- Server response 550
- SMTP prohibited by administrator
- Error 0x800ccc79
Security issues
All Internet and Network servers require that users login using their username and password to send and receive e-mail.
Verify that you are entering the correct username and password when attempting to send or receive your e-mail. If you are not being prompted for a username or password, it is likely that the username and password are configured within the e-mail program. Verify that the correct username and password have been entered into the e-mail program's configuration.
Note: Some network administrators or Internet service providers may expire your password after a length of time. If the password is not changed within that time period it is possible that you will no longer be able to receive e-mail until the password is changed.
Spam filter
Spam filters can inappropriately cause you to not receive e-mail. If a spam filter is improperly configured or your ISP believes a message is a spam, it will either placed in the Spam folder or deleted before you can read it. Only your Internet service provider can tell you if this is occurring.
Almost all e-mail programs today have some protection that helps protect users from spam. These programs, scripts, and add-ons can also cause e-mail to be wrongly deleted. If you have problems getting e-mail, make sure all spam filters are disabled on your end as well and no mail is in the junk or spam folder, or in the trash bin.
E-mail program corruption or other issues
If you have checked or verified each of the above recommendations and are still unable to receive or send e-mail, the e-mail program may have issues. Try uninstalling and re-installing your e-mail client. Alternatively you could also try an alternative e-mail client or service.