There are a couple of common reasons why your mint might fail and show as incomplete.
1. The Solana network might be slow or down
Check the status of the Solana network. Too much activity can slow the Solana network, and if the network is down, transactions won’t be completed. If there are still mints available, you can refresh the collection page and try to mint again when the Solana network is up.
2. The mint has completed and no NFTs are available
To check if this is the issue, refresh the mint page to see whether the mint has finished. After the collection reaches the total number of mints available, OpenSea will display the secondary collection. If you missed the minting window, you may still be able to get an NFT from this collection by purchasing it from another user.
You can always click the transaction link to see if the action was completed on-chain.