OS: Mac 10.15.3
Version: 4.0.12
1.Signed the transaction by wallet1 and wallet2,
result:
Broadcast fail with error message "An error occurred broadcasting the transaction".
And there is no other details.

Ok, can you do the following:
-v option: /Applications/Electron-Cash.app/Contents/MacOS/Electron-Cash -v/Applications/Electron-Cash.app/Contents/MacOS/Electron-Cash above with the path to your Electron-Cash.app bundle -- but only if you didn't put it in /Applications. If you did put it in Applications, just do step (2) above.If the above instructions are too complicated -- I just thought of something easier. After you sign the transaction -- click on this in the Transaction dialog to copy the transaction data to clipboard. And paste the text here. I can try broadcasting it to see what the error message is:

Oh wait. I just realized what the problem is!!! For some reason Electron Cash is signing this transaction with schnorr -- but we never implemented multisig schorr!!
Can you go to preferences and disable Schnorr for this wallet?
This must be a bug -- that shouldn't be allowed to happen in the UI.


It seemed the multisig wallet does not got this option.
But I disable it in the cosigner wallet. I will try it again.
Yes, broadcast successfully.You are right.Thanks a lot.
Yay! Glad it worked out.