Looks like I lost all my coins because my own stupidity.
Here is a story.Couple of years ago I generated offline wallet from bitaddress.org and printed out my Public/private keys with QR codes.
Then I checked the status of my wallet by using Public key via
https://bitref.com/ and I could see all my transactions perfectly fine.
Now I decided to sell some coins just to find out that none of common desktop wallets can import my private key.I tried Exodus,Electrum,Mycelium,they all say the key is invalid.
I tried to enter it by either typing manually or scan QR code, same result.
The private key is 52 characters starts with "L" which based on my research is Private Key WIF Compressed.
I tried all kind of decoding tools like
https://iancoleman.io/bitcoin-key-compression/http://lenschulwitz.com/base58https://www.better-converter.com/But no luck, none of them can recognize my private key.
I still can see all my balance no problem using public key.
Then I tried to repeat same process again and generated new offline wallet from bitaddress.org and tried to import the newly generated private key into desktop wallets and it worked perfectly fine... but not the key I made two years ago where all my coins are ;-(
Feeling devastated... Please help if possible.
Thank you.