“Error: Could not allocate vin”

If you received this error it is because your txid is invalid.
To verify that your TXID and Output Index are correct, open the debug console of your wallet and type the command:

masternode outputs

The list of valid TXIDs for masternodes will be shown. The first column is the TXID and the second column is the Output Index.

If your TXID does not appear in the list your masternode will not start, in which case you should create a new TXID:

Recreating TXID

If your txid appears in the list make sure it is configured correctly on the system:

Click the item to change according to the response of the command masternode outputs. If you change copy the new line generated in the button: masternode.conf >> Show