We also have this issue and have not found a way to resolve it. Often, it takes our clients multiple times to connect. This even occurs when everyone is on the local network. I've also noticed (using Task Manager) that the Java SE binary application is using 30% of the CPU (all by itself) when D20Pro is running (even when it is just sitting there). And then the total CPU usage can easily jump over 100% if other applications are started when D20Pro is running.