The ledger is added to every 10 minutes of so. When you broadcast to the network that you have found a block your transaction is tested. At any point along the way if you have errors then the block is dropped. You need to have the hash of the previous block plus have met the diff goal on your block. This will be checked. If you have not met the diff then the block is rejected out of hand by the network.
Now, if you did meet the diff requirements then you have, indeed found a block and added it to the blockchain.
You use words "
dropped", "
rejected" without explaining how this is technically implemented. So far, only one thing is clear: the block is in the blockchain if it receives confirmations (consensus in the network). "Confirmation" means that subsequent blocks include its hash as the previous block's hash. But
what happens to the blocks that were proposed, but for various reasons didn't end up in the longest chain? Are those still in the ledger?