Private Key not recognized

I have a Litecoin paper wallet generated in 2017. My address on the blockchain shows 5.8 coins. Electrum v. desktop wallet shows 4 transactions equaling 5.8 coins but the sweep button will not activate when I try to sweep my private key. Can I sweep my private key in Litecoin Core version v0.18.1 (64-bit)?

What program did you use to generate your paper wallet?

I found a solution. I used the Litewallet scan function. Thanks for your reply.