Hello all, for some reason, I cannot send emails from tools>email to any address. it just says "send email failed"

I checked with my host and everything is correct. my other email functions work. when accounts are created, orders submitted. that works

but when I try to initiate an email to customer. it fails
I have attached my email settings here for anyone to review

is there something else I should have configured

Value Action
E-Mail Transport Method smtp
E-Mail Linefeeds LF Info
Use MIME HTML When Sending Emails true Info
Send E-Mails true Info
Email Archiving Active? true Info
E-Mail Friendly-Errors true Info
Email Address (Displayed to Contact you) [email protected] Info
Email Address (sent FROM) [email protected] Info
Emails must send from known domain? Yes Info
Email Admin Format? HTML Info
Send Copy of Order Confirmation Emails To [email protected] Info
Send Copy of Create Account Emails To - Status 1 Info
Send Copy of Create Account Emails To [email protected] Info
Send Copy of Tell a Friend Emails To - Status 1 Info
Send Copy of Tell a Friend Emails To [email protected] Info
Send Copy of Customer GV Send Emails To - Status 0 Info
Send Copy of Customer GV Send Emails To [email protected] Info
Send Copy of Admin GV Mail Emails To - Status 0 Info
Send Copy of Customer Admin GV Mail Emails To [email protected] Info
Send Copy of Admin Discount Coupon Mail Emails To - Status 0 Info
Send Copy of Customer Admin Discount Coupon Mail Emails To [email protected] Info
Send Copy of Admin Orders Status Emails To - Status 0 Info
Send Copy of Admin Orders Status Emails To [email protected] Info
Send Notice of Pending Reviews Emails To - Status 0 Info
Send Notice of Pending Reviews Emails To [email protected] Info
Set "Contact Us" Email Dropdown List Info
Allow Guest To Tell A Friend true Info
Contact Us - Show Store Name and Address 1 Info
Send Low Stock Emails 0 Info
Send Low Stock Emails To [email protected] Info
Display "Newsletter Unsubscribe" Link? true Info
Audience-Select Count Display false Info
SMTP Email Account Mailbox [email protected] Info
SMTP Email Account Password ********* Info
SMTP Email Mail Host mail.prokarate.com Info
SMTP Email Mail Server Port 25 Info
Convert currencies for Text emails £,£:€,€ Info
Send Notice of Newsletter-only Subscriptions To - Status 1 Info
Send Notice of Newsletter-only Subscriptions To [email protected]