Mixers usually have a somewhat stricter firewall setup, I wouldn't be surprised if the firewall temporarily blocked you because you made several access attempts in a short period.
The same thing happened to me with other mixers, but after a while it resets and access is enabled again.
I know what you mean, but it wasn't because I was sending too many connection requests to the server. The server gave me a 502 error the first time I tried to access the mixer, I waited for a while and got the same result, this continued for about another hour, then I gave up and didn't try again. These kinds of mistakes are sometimes normal, but since it was a mixer, I feared the worst.