If you are not receiving any e-mails from LiveJournal, please verify that the e-mail address on your account is correct by visiting http://www.livejournal.com/editinfo.bml. Also, ensure that your e-mail address is validated (http://www.livejournal.com/support/faqbrowse.bml?faqid=11).
If you are not receiving comment notification e-mails, check to ensure that you have your message boards enabled and that you have enabled the "Get message board replies" option (http://www.livejournal.com/support/faqbrowse.bml?faqid=62). If you have enabled HTML e-mails, try turning this option off.
If the above solutions don't work, check the space available in your e-mail account. Many e-mail service providers place limitations on the amount of e-mail you can store in your mailbox. If you have space available in your mailbox, then it is likely that some or all of your LiveJournal e-mail is being filtered or blocked as spam or junk mail. Check the spam or junk mail filters on your e-mail account. If it is possible for you to adjust or edit them, add livejournal.com to the "allowed senders" list (sometimes called a "whitelist"). If it is not possible for you to adjust or edit them, you may need to disable them entirely. Also, certain Internet services provide parental controls which can interfere with proper e-mail delivery.
If you have adjusted or disabled the spam or junk mail filters on your e-mail account, or do not know how to do so, and are still not receiving LiveJournal e-mail, you will need to contact your e-mail service provider for further assistance, and tell them that you are not receiving legitimate e-mails from livejournal.com. Many e-mail providers are not aware of the mail filters they have in place. The most popular mail transport package, "sendmail", comes with mail filters enabled by default that appear to block some LiveJournal e-mail.
Also, other e-mail providers implement filters which apply to all accounts in addition to any filters which users can control. These types of filters are often implemented to control bandwidth expenses, and block messages on certain criteria which may vary. Many e-mail providers do not notify their customers that such filters are used. An example of these filters would be blocking comment notifications based on the subject line "Reply to your post", since that is also a common falsified subject line used by spammers. Another example would be an e-mail server that blocks livejournal.com because LiveJournal sends a high volume of automatic e-mails. Still other e-mail providers may simply block LiveJournal entirely, for reasons of their own which they might not disclose. You must contact your e-mail service provider directly to inquire about the filters they use and whether they may be affecting e-mail delivery to your account.
If, after following all of the above suggestions, including contacting your e-mail service provider, you are unable to receive e-mails from LiveJournal reliably, you may want to choose a different e-mail address to receive LiveJournal e-mail (http://www.livejournal.com/support/faqbrowse.bml?faqid=19). Please note that your new e-mail account may suffer from the same types of restrictions, and you may have to try several different e-mail providers until you find one which works with LiveJournal reliably.