Server shows up on list, friend can't join

I tried searching for help on this, but so far have not found anything which would help me.

I was running a server just fine before, but then I went and changed my internet provider. I received a new ADSL modem/router and put in the port forwarding settings for port 10308. I did this for both TCP and UDP. My firewall already had these ports in from before.

Now my server shows up on the server list but for some reason my friend can't join in anymore.

Any suggestions?