My light wallet is showing an incorrect balance or says I'm not delegated to a Stake Pool
Cardano light wallets such as Yoroi, Eternl, Flint, Typhon, and others rely on servers to keep the blockchain information up to date. If you notice incorrect balances in your wallets, if your wallet says you are not delegated to a stake pool, or if you have some other issue, it may just be that the servers behind the wallet are experiencing sync issues.
Think of the aforementioned wallets more as wallet interfaces. Your wallet is on the blockchain and Yoroi, Eternl, Flint, Typon, and others are just software applications you can use to view and interact with your on-chain wallet.
To view your actual balance, stake pool delegation, and more, you can enter your address (starting with 'addr1') or your stake key (starting with 'stake1') into cardanoscan.io. The 'Controlled Stake' section on the platform will show your whole balance including staking rewards.
To fix your wallet interface issues you could try resyncing. You can find a resync option in the settings of most light wallets. If this doesn't fix your issue and your wallet interface is still showing a different balance to cardanoscan.io, then you can use your seed phrase or hardware wallet to set up your wallet in a different wallet interface. You can have your wallet set up in multiple wallet interfaces at the same time, this also enables you to try the interfaces out and see which one is best for your needs.
Switching between wallet interfaces is a lot more secure when using a hardware wallet such as a Ledger or Trezor as you avoid the need to enter your seed phrase each time. See 'Should I get a hardware wallet?'.