Closing Lightning channel: "Funding transaction not found." & "Failed to close channel: TxBroadcastServerReturnedError"

[Geremia]

When I try to close a Lightning channel with master (Electrum 0df05dd), I get this error:

Failed to close channel:
TxBroadcastServerReturnedError('bad-txns-inputs-missingorspent\nYou might have a local transaction in your wallet that this transaction builds on top. You need to either broadcast or remove the local tx.')

I don't think I have any pending local transactions, so I'm not sure why it thinks I "might have a local transaction in your wallet that this transaction builds on top".

The channels I'm trying to force-close have been stuck on REESTABLISHING.

"Funding transaction not found."

A solution in the BitcoinTalk.org post "Electrum funds stuck in lightning. Unable to force close channel" mentions correcting the funding_outpoint in my wallet, but in my case the funding transaction doesn't appear in my wallet.

Closing the channel with close_channel in the console makes Electrum hang.

[bitromortac]

With latest master it is not possible to cooperatively close channels, which did not send lots of payments due to a regression, which should be fixed by #7588.

[SomberNight]

so I guess this can be closed