About blockchain.info API HELP I use the blockchain.info API to generate unique addresses each time to receive bitcoins.

This works. However, when an address was generated but a payment only gets confirmed a few days later, even if you login to blockchain.info, it will not appear in the transaction list.

The gap is not regenerated. What can I do?
Well, seems like a "gap" limitation problem !

As defined in BIP 44, wallet software will not scan past 20 unused addresses.

There is 2 solutions:

1 - do not show bitcoin address directly to user, generate 20 addresses, save them in into an database and once a user want to pay you using bitcoin, you fetch the address from your database.

2 - (solution provided by blockchain) You need to switch to a new xPub key after each 20 generated addresses (within the same wallet).