The error means that you have signed the transaction with a wrong private key. In other words, you couldn't prove that you own the coins you are trying to spend.
How did you create your wallet?
Do you have the seed phrase? If so, create a new wallet. Maybe, the wallet file is corrupted.
If you haven't created the wallet by yourself and you have purchased the wallet file, you have been scammed.
Really? can you explain, what electrum wallet can made fake wallet? I created this wallet around 2014, but I've changed computers more than 4 times. I just copy wallet.dat every move from old computer.
