I’ve read that by standard first part of e-mail is case sensitive, however I’ve tried to send e-mail to name@example.com, Name@example.com and NAME@example.com – it has arrived in each case.
How do mail servers handles usernames? Is it possible to miss with case and that message wouldn’t be delivered? Is it really very important to use exactly same letter case, as was written while registering when giving your e-mail address?