This used to happen when I hosted TF2 Servers, If you have more than one server then one of the servers will struggle UNLESS you make sure the second server is on a different port. Example: Say your first port is 100, You could make your second one 101 and it should stop any issues.
Are the servers running on different ports and are both ports forwarded?
Not too hard to check out
http://master2.blockland.us/ or start Blockland up to see for yourself.
Much faster than waiting for a reply.
And also it's a hosting service, the ports should already be fowarded, shouldn't it?
This seems to be a fairly common issue with Blockland with no luck at what exactly causes it or any good solid solutions.
I'd suggest changing the ports to something else, or shut down the server for a minute and start it back up to see if that helps at all.