This error doesn’t indicate that your canister is unresponsive. This CycleOps error actually indicates that someone else has added this same canister id to their account. Are you monitoring this canister in a different CycleOps account (individual/team account)? If so, for blackhole monitoring we only allow a single account to monitor a specific canister once you’ve added our blackhole as a controller and verified ownership of the canister in order to ensure data privacy.
If you want to transfer canisters between your accounts (from individual to team accounts), you can use canister projects and CycleOps teams to transfer canisters between accounts and preserve historical metric data.
Alternatively, you can delete the canister from the previous account and then add it to the new account (although the historical metric data for that canister will not carry over in this case).