Try this to run multiple masternodes on the same linux vps.

Review under /home/yourusername/.das the das.conf file

I have the following config in it:

server=1
daemon=1
listen=1
rpcuser=dasuser01 >>> your RPC user
rpcpassword=asdfuh2q3r98zasFHBas90dfh213AHdfkajg234 >>>your RPC password
rpcport=9398 >>> some RPC port
rpcallowip=127.0.0.1
masternode=1
masternodeprivkey=<<< your Masternode genkey >>>
masternodeaddr=13.284.238.21 >>> your linux VPS WAN/external IP address
externalip=13.284.238.21 >>> your linux VPS WAN/external IP address
bind=10.0.1.4:9399  >>> your internal linux vps IP address with the DAS port - which is bound to the 1st WAN IP

Then start your masternode with: dasd --datadir=/home/yourusername/.das

For your second masternode on the same machine:
- Requirement: You need a second WAN IP / external IP address for your 2nd Masternode.

- Make a second das folder: mkdir /home/yourusername/.das1
- create a empty das.conf with nano das.conf in it.

Config for the second masternode:

server=1
daemon=1
listen=1
rpcuser=dasuser02 >>> your 2nd RPC user
rpcpassword=aSf92hAGHBf29o83hzgaökdfabdf >>>your 2nd RPC password
rpcport=9397 >>> your 2nd RPC port
rpcallowip=127.0.0.1
masternode=1
masternodeprivkey=<<< your 2nd Masternode genkey >>>
masternodeaddr=93.293.23.235>>> your 2nd linux VPS WAN/external IP address
externalip=93.293.23.235 >>> your 2nd linux VPS WAN/external IP address
bind=10.0.1.5:9399  >>> your 2nd internal linux vps IP address with the DAS port - which is bound to the 2nd WAN IP

Then start your 2nd masternode with: dasd --datadir=/home/yourusername/.das1