I'm now trying to increase the fees for transaction 3. The current fee for transaction 3 is 7 sat/b, but even I put in 27 sat/b, it still says:

the server returned an error when broadcasting the transaction. Consider trying to connect to a different server, or updating Electrum

insufficient fee, your transaction is trying to replace another one in the mempool but it does not meet the rules to do so. Try to increase the fee.

[/quote]


I set the fees to 30 sat/b, and now it changed

At the same time, it shows that transaction 1 and 2 are invalidated