Custom program error

0x21fc8700

Appears in logs as custom program error: 0x21fc

Anchor

Custom error #2700

“custom program error: 0x21fc”

Code 8700 (0x21fc) is not an Anchor framework error. Anchor programs number their own #[error_code] enum starting at 6000, so this is the 2701st variant (index 2700) of the error enum defined by the program you called.

Common causes

  • The program's instruction handler returned the error at index 2700 of its custom error enum. What that means depends entirely on the program.

How to fix it

  • Look at the program logs: Anchor prints Error Code: <Name>. Error Number: 8700. Error Message: <text> just before the failure.
  • Open the program's IDL (on an explorer or via anchor idl fetch <programId>) and find the errors entry with code 8700.
  • In the Rust source, count variants in the #[error_code] enum: variant 2700 (zero-based) is the one that fired.
Source definition ↗All Anchor errors →

How Anchor custom error numbers work

Every Anchor program declares its own errors with #[error_code]. Anchor assigns the first variant 6000, the second 6001, and so on, so they never collide with the framework’s own errors (100–5999). The hex you see in logs is simply that number in base 16: 6000 = 0x1770, 6001 = 0x1771, 6002 = 0x1772.

#[error_code]
pub enum MyError {
    #[msg("Amount must be greater than zero")]
    ZeroAmount,          // 6000 = 0x1770
    #[msg("Slippage tolerance exceeded")]
    SlippageExceeded,    // 6001 = 0x1771
    #[msg("Pool is paused")]
    PoolPaused,          // 6002 = 0x1772
}

To find out what 0x21fc means for the program you called, fetch its IDL and look at the errors array, or look for the Error Message: log line Anchor prints before the failure. The transaction decoder pulls these log lines out of a failed signature for you.

Decode another error

Try:

Nearby codes

0x21f9Custom error #26970x21faCustom error #26980x21fbCustom error #26990x21fdCustom error #27010x21feCustom error #27020x21ffCustom error #2703