iptables forwarding not working?

Hello, i am trying to setup a iptables rule to forward port 49 traffic from a specific ip a.a.a.a to port 50, but it does not seem to work, can someone take a look at my rule and let me know why it is not working? thanks

iptables -t nat -A PREROUTING -s a.a.a.a/32 -p tcp --dport 49 -j REDIRECT --to-port 50

With your subnet mask of /32, its possible your source address is not matching correctly. With a mask of /32 that allows 1 IP address. Try "-s a.a.a.a/24", this means for the last octet can be in the range of 1-254.