validating typeos in email on c#

We have a lot of emails being manually typed into one of our 开发者_如何学运维services. We do the normal email regular expression checks but occasionally one of them is a typeo for example contactmee@gmail.com instead of contactme@gmail.com. Does anyone know of any more extreme validation lengths we can go to reduce instances of this? Our service runs on windows and has access to the internet.

What is the input mechanism for these emails - a form?

The traditional method of eliminating typos is having 2 fields; Email and Re-enter Email. Disable copy-pasting into the 2nd field to force them to type it again. That way, the chance of the same typo being made twice is greatly reduced.