When you achieve to send a transaction, this track is noticed on your list of operations as pending confirmation, then it is confirmed later - regularly after about 10mn, up to a couple hours.
This delay depends on
If your transaction is marked as "Unconfirmed" more than tens of minutes, it means that it is not confirmed yet by blockchain miners. To track your transaction, click on it in your list of operations, and click on the magnifying glass, you'll see your transaction directly on a blockchain explorer.
If it doesn't match with what is displayed on your Ledger Wallet Bitcoin application, please:
In some cases, your transaction can remain unconfirmed a long time, up to several days. It is most of the times when you want to send a transaction constituted of a lot of inputs due to multiple small payments, or due to the fact that you receive a huge number of small transactions, that are very hard to spend all in once.
If this happens, you need to be patient, and wait for your transaction to be achieved, even if it can take days, or wait until it is definitively rejected by the miners. When it is rejected, your operation will disappear of your list of operations in your Ledger wallet.
When a transaction takes too long to be confirmed, some people tries to spend these same coins another time, before the first transaction is achieved, for example by forcing it with higher fees. It is not possible with Ledger wallets yet.