Outlook invalid email address / invalid recipient
From time to time, Outlook may mistakenly report recipients as having invalid email addresses, although their email addresses are clearly valid. In this article we try to offer some solutions to this “invalid email address” Outlook error.
One product affected by this error is Easy Mail Merge for Outlook. While sending mass emails, Outlook may trigger an error reporting that the recipient’s email address is invalid. This error can also happen when you compose a regular email and send it to one of your contacts.
Solution 1 – empty auto-complete list
Usually, the “invalid email address” error happens when you have 2 or more contacts with the same name, but one of them doesn’t have a valid email address. The solution is to empty the Outlook auto-complete list.
To empty the list, you have to go to the Outlook File menu -> Options -> Mail -> scroll to the Send Messages section -> click on “Empty Auto-Complete List”.
Solution 2 – disable Outlook automatic name checking
Go to the Outlook File menu -> Options -> Mail -> scroll down to the “Send Messages” section -> un-mark the option “Automatic name checking”.
Solution 3 – check Outlook data files for errors
Sometimes, Outlook data files may become corrupted. causing all sorts of errors. It is never a bad idea to check the data files for problems: see this Microsoft tutorial.
Solution 4 – create a new Outlook profile
Try to create a new Outlook profile and see if the error still happens: https://support.microsoft.com/en-us/kb/829918.