Validation error: "It cannot be more than one connector between the same two elements"
I am trying to model one of our processes, and in this model, different tasks in different pools in the same milestone should be connected by message flow connectors to show that they send and receive messages. My problem is although this seems logical, I keep getting the error message of "It cannot be more than one connector between the same two elements" whenever I want to validate the process. Another problem is when I create the exact process model on another computer, it doesn't show the error. So, now I am confused about this kind of connection. Are we allowed to have two connectors between two elements in different pools or not?