Solana errors, explained

Wallets show you a program error code and almost no context. Here is what the common ones actually mean, and the shortest route out of each.

• Transaction simulation failedYour wallet rejected the transaction before it reached the chain, which is good news: nothing was spent. The useful part is the code hiding behind the message.
• custom program error: 0x1The token program reporting that the account does not hold as much as the instruction is trying to move. Adding SOL will not help, because SOL is not what ran out.
• custom program error: 0xbThe account you are closing is not empty. Almost always a fraction too small for your wallet to display, left behind by a partial fill or a rounding remainder.
• custom program error: 0x23A Token-2022 account reads as zero but is not closeable, because the transfer fee extension parked withheld fees inside it. One extra instruction clears it.

Seeing insufficient funds for rent instead? That one is about the SOL deposit every account has to hold, and it has its own write-up.