I've been trying to use the stock email client in the Sharp 3.10 ROM (SL-5500)
to send authenticated emails, but I keep getting this message
whenever I try to send:

Sending Error

Unexpected response from server:

554 SMTP synchronization error

I've got the Authentication box checked on the Z and my authentication settings entered.

These same settings working fine in my email client on the desktop.

Any suggestions?