I just installed 6.5.5. Everything seems to be working. I am able to send a test e-mail to any address from admin->e-mail settings. I am using an SMTP server.
When I create a new user, I get a message:
Cannot send password
System is unable to process your request. Please check:
-SMTP Server URL and Port
-SMTP Username and SMTP Password
-Recipient Email Address
-Your server status