No. Email addresses are not case sensitive. Having letters in all lowercase makes the email address easier to read, but the oversight won't stop your messages from being delivered.

Are email passwords case sensitive?

In short, Email addresses ARE NOT case sensitive and Passwords ARE case sensitive. Email Addresses: When creating usernames for your email accounts, the username should be created in all lowercase letters. ... However, even if you do create it with UPPERCASE letters it will not matter anyway.

Can you use capital letters in an email address?

Do not use ALL capital letters to emphasize or highlight your message. This is considered to be rude, and can be interpreted as shouting at someone in terms of email etiquette.