But i really don't know why i got the error and how to prevent it from happenig again.
The only possible reason is Electrum have connected to a malicious server despite the added parameters in the shortcut.
That message will show if the server tried "
something else" other than broadcasting the transaction.
Try to edit Electrum's setting into
"oneserver"=true.
You can find it in %appdata%/Electrum/config (
open with notepad).
[%appdata% = Win+R->type %appdata%]