diff --git a/src/domain/checkForAndPlaceOrder.ts b/src/domain/checkForAndPlaceOrder.ts
index 471da63..2cb2556 100644
--- a/src/domain/checkForAndPlaceOrder.ts
+++ b/src/domain/checkForAndPlaceOrder.ts
@@ -38,6 +38,7 @@ import {
   totalPollingOnChainChecks,
   totalPollingRuns,
   totalPollingUnexpectedErrors,
+  totalPollingOnChainEthersErrors,
 } from "../utils/metrics";
 
 const GPV2SETTLEMENT = "0x9008D19f58AAbD9eD0D60971565AA8510560ab41";
@@ -529,6 +530,7 @@ async function _pollLegacy(
   const { contract, multicall, chainId } = context;
   const logPrefix = `checkForAndPlaceOrder:_pollLegacy:${orderRef}`;
   const log = getLogger(logPrefix);
+  const { handler } = conditionalOrder.params;
   // as we going to use multicall, with `aggregate3Value`, there is no need to do any simulation as the
   // calls are guaranteed to pass, and will return the results, or the reversion within the ABI-encoded data.
   // By not using `populateTransaction`, we avoid an `eth_estimateGas` RPC call.
@@ -537,6 +539,8 @@ async function _pollLegacy(
     "getTradeableOrderWithSignature",
     [owner, conditionalOrder.params, offchainInput, proof]
   );
+  const id = ConditionalOrderSDK.leafToId(conditionalOrder.params);
+  const metricLabels = [chainId.toString(), owner, handler, id];
 
   try {
     const lowLevelCall = await multicall.callStatic.aggregate3Value([
@@ -573,12 +577,13 @@ async function _pollLegacy(
       target,
       callData,
       revertData: returnData,
+      metricLabels,
     });
   } catch (error: any) {
     // We can only get here from some provider / ethers failure. As the contract hasn't had it's say
     // we will defer to try again.
-    // TODO: Add metrics to track this
     log.error(`${logPrefix} ethers/call Unexpected error`, error);
+    totalPollingOnChainEthersErrors.labels(...metricLabels).inc();
     return {
       result: PollResultCode.TRY_NEXT_BLOCK,
       reason:
diff --git a/src/utils/contracts.ts b/src/utils/contracts.ts
index 2d01bad..4859ebc 100644
--- a/src/utils/contracts.ts
+++ b/src/utils/contracts.ts
@@ -8,6 +8,7 @@ import {
   SupportedChainId,
 } from "@cowprotocol/cow-sdk";
 import { getLogger } from "./logging";
+import { totalPollingOnChainInvalidInterfaces } from "./metrics";
 
 // Selectors that are required to be part of the contract's bytecode in order to be considered compatible
 const REQUIRED_SELECTORS = [
@@ -196,8 +197,17 @@ export function handleOnChainCustomError(params: {
   target: string;
   callData: string;
   revertData: string;
+  metricLabels: string[];
 }): PollResultErrors {
-  const { owner, orderRef, chainId, target, callData, revertData } = params;
+  const {
+    owner,
+    orderRef,
+    chainId,
+    target,
+    callData,
+    revertData,
+    metricLabels,
+  } = params;
   const logPrefix = `contracts:handleOnChainCustomError:${orderRef}`;
 
   try {
@@ -287,6 +297,7 @@ export function handleOnChainCustomError(params: {
     log.debug(
       `Contract returned a non-compliant interface revert via getTradeableOrderWithSignature. Simulate: https://dashboard.tenderly.co/gp-v2/watch-tower-prod/simulator/new?network=${chainId}&contractAddress=${target}&rawFunctionInput=${callData}`
     );
+    totalPollingOnChainInvalidInterfaces.labels(...metricLabels).inc();
     return {
       result: PollResultCode.DONT_TRY_AGAIN,
       reason: "Order returned a non-compliant (invalid/erroneous) revert hint",
diff --git a/src/utils/metrics.ts b/src/utils/metrics.ts
index c753b6e..c3b7ded 100644
--- a/src/utils/metrics.ts
+++ b/src/utils/metrics.ts
@@ -108,6 +108,18 @@ const pollingOnChainDurationSeconds = new client.Histogram({
   labelNames: ["chain_id", "handler", "owner", "id"],
 });
 
+const totalPollingOnChainInvalidInterfaces = new client.Counter({
+  name: "watch_tower_polling_onchain_invalid_interface_total",
+  help: "Total number of invalid on-chain hint interface",
+  labelNames: ["chain_id", "handler", "owner", "id"],
+});
+
+const totalPollingOnChainEthersErrors = new client.Counter({
+  name: "watch_tower_polling_onchain_ethers_errors_total",
+  help: "Total number of ethers on-chain hint errors",
+  labelNames: ["chain_id", "handler", "owner", "id"],
+});
+
 const totalPollingUnexpectedErrors = new client.Counter({
   name: "watch_tower_polling_unexpected_errors_total",
   help: "Total number of unexpected polling errors",
@@ -132,6 +144,8 @@ export {
   totalOrderBookErrors,
   totalPollingRuns,
   totalPollingOnChainChecks,
+  totalPollingOnChainInvalidInterfaces,
+  totalPollingOnChainEthersErrors,
   pollingOnChainDurationSeconds,
   totalPollingUnexpectedErrors,
 };
diff --git a/src/utils/utils.spec.ts b/src/utils/utils.spec.ts
index 2e90c03..a0048c6 100644
--- a/src/utils/utils.spec.ts
+++ b/src/utils/utils.spec.ts
@@ -100,6 +100,7 @@ describe("handle on-chain custom errors", () => {
     revertData: abiToSelector(
       CUSTOM_ERROR_ABI_MAP[CustomErrorSelectors.SINGLE_ORDER_NOT_AUTHED]
     ),
+    metricLabels: [],
   };
 
   it("should pass a known selector correctly", () => {