I am trying to send some iotas and this message keeps popping up. What am I doing wrong? How to find out which node to select in order to get transactions confirmed?
Check if you already made the transaction and if it is pending, if so just promote it instead of trying to create a new transaction. Other possibility is that you are trying to send to an address that has already been used.
If you know what you are doing and really need to ignore this advice you can use the CLI wallet https://github.com/iotaledger/cli-app.