Nonce blockhash not expired
System Program · Custom(7) · 0x7
custom program error: 0x7
What it means
The durable nonce was advanced twice in the same slot, so its stored blockhash has not changed yet.
What to do
Wait one slot before advancing the nonce again, and never reuse a nonce across two in-flight transactions.
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 7 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.