subnet_not_exists

The netuid does not name an existing subnet on this network.

Netuids are not stable across networks: a subnet that exists on finney may not exist on testnet. btcli subnets list shows the valid netuids for the network you are connected to (check --network).

Remediation

Use an existing netuid; btcli subnets list shows valid ones

Chain errors

The exact chain error names (from the extrinsic receipt) that classify to subnet_not_exists; the description says what triggered the failure and where to check. Each name has its own page:

Chain error	Description
MechanismDoesNotExist	The target subnet or its sub-mechanism does not exist: the netuid is unknown, the mechanism index is at or above MechanismCountCurrent, or a non-dynamic mechid was requested. Check the netuid with btcli subnets list and the mechanism count for that subnet.
RootNetworkDoesNotExist	Root registration or root stake claiming found no root network in chain state, which only happens on misconfigured or freshly bootstrapped chains. Verify netuid 0 exists in NetworksAdded.
SubnetDoesNotExist	The admin-utils call targets a netuid with no registered subnet. Verify the netuid argument against NetworksAdded (the set of existing subnets) before setting hyperparameters.
SubnetNotExists	The netuid passed to the call does not correspond to a registered subnet. Verify the netuid argument against NetworksAdded or btcli subnets list; the subnet may also have been dissolved.

The same explanation is available in the terminal: btcli explain subnet_not_exists (or btcli explain <ChainErrorName> for one exact chain error).