Bitcoin explorers don't show my addresses transactions
Check that this is the actual address that you used to receive the Bitcoin in the past. 

The default behavior for wallets is to generate a new address each time you want to receive funds. This means that if you simply opened your wallet, hit generate, and tried to scan that address, it will show 0 transactions. And, this is correct, because even though the wallet has received Bitcoin, that specific address hasn't.