This local transaction will be spending existing inputs and creating new UTXOs, when you attempt to send a 2nd transaction, it'll be attempting to spend these new UTXOs that only exist on YOUR wallet... as the previous transaction has not been broadcast. Thus, the server will reject your transaction due to "missing inputs" as it can't find these UTXOs that you're trying to use.
Solutions:
1. Broadcast the local transaction to the network and then send new transaction.
or
2. Delete the local transaction and then send new transaction.
I'd recommend that you check if you actually want that "local" transaction to be broadcast or not. You can right click and select "details" and check the amount and output addresses etc. If you don't want that transaction, you can delete it, by right clicking it and selecting "remove"