If you aren't sure that an e-mail address is valid, or that it works, you can check it in several different ways. This allows you to filter out bad e-mails or e-mail addresses that are incorrect. You will have a more professional business, or an easier time conducting business, if you only use valid e-mail addresses.
Send an e-mail to the email address. This is the best way to check to see if an e-mail address is valid. Most of the time, if the email address is not valid, it will bounce back to you, and you will receive a message stating that the email address does not work. Then, you can remove those e-mail addresses from your list, or ask the person for a different e-mail address.
Use an online e-mail verification form, like Verify Email Address. These online sites will send verification messages to e-mail accounts, and tell you whether or not they are working. There are hundreds of others that you can choose from by doing a simple search engine search. Check reviews of them first, to make sure you aren't visiting a scam site.
Go to the email verification site and input the address into the verification form on the website and click "verify." You will receive an answer right away a to whether or not the email address is valid.
Although time consuming, sending an e-mail and waiting for a reply, or a "failure" message, is really the best way to check e-mail addresses.
Be careful about e-mail verification sites. Check a review of them first because some of them might be spam sites or phishing sites. Don't just input e-mail addresses into the first site you see.