Reply To: Server Failed

I haven’t had that situation, but as far as I know that should work. The 3 in the middle shows that the port is reachable by an external sender.
I have 321 and have seen 331 working. But it might be the case that at that time Alex was working on something and therefor the connections didn’t work for some time or under certain circumstances. I has problems a few days ago too.
The first and last digit shows characteristics of your router. They are built into the router and most probably cannot be modified. But the 3 in the middle shows that your port forwarding works.

Just try again. If it still does not work, you best contact Alex directly.