Error codes / 0x38
custom program error: 0x38
Custom(56) · 0x38 · used by 2 programs we know
This number has no meaning on its own. Each Solana program numbers its own errors, so 0x38 is UnknownAmmError in Raydium AMM V4 but SpotMismatch in Metaplex Token Metadata. The meaning that applies is the one from the program that actually failed: the first Program … failed line in the transaction's logs. That is often not the program you called, but one it invoked, or a guard instruction your wallet added.
Don't guess: paste the transaction
TxWhy reads the logs, finds the program and the exact instruction that raised 0x38, explains it, and rebuilds the transaction when the cause is one it can fix.