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.

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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.