Bugs regarding Multiple Masternodes on same VPS

1. Another port than 9399 on local masternode.conf
"Error reading masternode configuration file: Invalid port detected in masternode.conf. … (must be 9399 for mainnet)

2. Starting second dasd daemon on VPS
Error: Unable to start HTTP server. See debug log for details.
Only works with another port, same old problem local wallet wont work with another port --> Bug/Impossible

But I have to use a another port... Otherwise it won't start.

Whats up here? Why no other port? Why no other daemon? What "HTTP" Server?
I am confused...