CRM 4 - Invalid email Error when creating an Appointment

Error Message: Invalid e-mail address. For more information, contact your system administrator.

You might get an error message when creating an appointment stating invalid email address. When you check the records you will see that the email address is correct and you might be wondering why on earth that you are getting an error message like this. 

The reason is simple. although your email address is a valid email address if one the letters contain an invalid character the you get this error message.

e.g: abdñaddd@test.com

The letter n contains and invalid character for the email address. Once you get rid of that this would start working fine.

e.g: abdnaddd@test.com