Hi,
The error “Multiple Solver Blocks connected to physical network. Each physical network must be connected to exactly one Solver Configuration block” generally arises when there are multiple solver blocks connected to the network.
I tired to reproduce the issue from my end.
In the first picture, notice that there two Solver Configuration blocks which causes the error. And it can be solved by removing one of the Solver blocks. But in the screenshot attached to the question I could see only one solver block. Check if the blocks are overlapped. If the issue is not solved, try to remove all the connections, and reconnect them.
For more information refer Physical network Environment and Solver Configuration
