Hi,
How do I fix this error?
Daedalus? It should not produce such an error in the first place. It does not have the controls so that you can fix it.
The error says that the input to the transaction does not equal the output. Wallet apps should usually only produce balanced transactions.
Spontaneously, I’d see two possibilities: The node was not fully synced and Daedalus chose an input that in reality was already spent. So that the values of that input is missing from the transaction. Or – more or less a variation of that – you were doing two transactions in parallel – perhaps with different wallet apps or a dApp – and the other one grabbed an input from this one.
Just make sure that the wallet is fully synced and there are no other transactions pending and try again.