TooManyRegistrationsThisBlock

Registrations in the current block already reached the subnet's per-block cap (MaxRegistrationsPerBlock, the max_regs_per_block hyperparameter); root registration enforces the same cap on netuid 0. Retry in the next block.

Declared by the SubtensorModule pallet; it classifies to the semantic code rate_limited.

Remediation

Wait for the rate-limit window to pass, then retry

The same explanation is available in the terminal: btcli explain TooManyRegistrationsThisBlock.