Unexpected nonce value
System Program · Custom(8) · 0x8
custom program error: 0x8
What it means
The transaction's blockhash does not match the value stored in the nonce account. Another transaction used the nonce first.
What to do
Re-read the nonce account and rebuild the transaction with its current value.
Have the transaction that failed with this?
Paste its signature. TxWhy shows the exact instruction and inner call that raised the error, and rebuilds the transaction when the cause is one it can fix (compute limit, expired blockhash, priority fee, stale swap quote).
Code 8 means something else in other programs
Custom codes are private to each program. Check which program actually raised it: it is the innermost failed call, not necessarily the program you called.