--- a/toolkit/components/telemetry/Histograms.json
+++ b/toolkit/components/telemetry/Histograms.json
@@ -7108,16 +7108,36 @@
       "eRedirect",
       "abort",
       "timeout",
       "eTooLate",
       "eTerminated"
     ],
     "description": "Counts of the different ways sending a Telemetry ping can fail."
   },
+  "TELEMETRY_SEND_FAILURE_TYPE_PER_PING" : {
+    "record_in_processes": ["main"],
+    "alert_emails": ["telemetry-client-dev@mozilla.com", "chutten@mozilla.com"],
+    "bug_numbers": [1438896],
+    "expires_in_version": "66",
+    "kind": "categorical",
+    "keyed": true,
+    "labels": [
+      "eOK",
+      "eRequest",
+      "eUnreachable",
+      "eChannelOpen",
+      "eRedirect",
+      "abort",
+      "timeout",
+      "eTooLate",
+      "eTerminated"
+    ],
+    "description": "Counts the number of times a failure occures while sending a Telemetry ping. It is a keyed histogram where the type of ping will serve as the key and may include the following ping types : {common, main, deletion, crash, sync, new-profile, core, modules, environment, health, heartbeat, malware-addon-states, activation, saved-session, backgroundhangmonitor, first-shutdown, anonymous, uitour-tag}."
+  },
   "TELEMETRY_STRINGIFY" : {
     "record_in_processes": ["main"],
     "alert_emails": ["telemetry-client-dev@mozilla.com"],
     "expires_in_version": "never",
     "kind": "exponential",
     "high": 3000,
     "n_buckets": 10,
     "description": "Time to stringify telemetry object (ms)"

--- a/toolkit/components/telemetry/TelemetrySend.jsm
+++ b/toolkit/components/telemetry/TelemetrySend.jsm
@@ -1103,16 +1103,17 @@ var TelemetrySendImpl = {
       this._log.trace("_doPing - Can't send ping " + ping.id);
       return Promise.resolve();
     }
 
     if (this._tooLateToSend) {
       // Too late to send now. Reject so we pend the ping to send it next time.
       this._log.trace("_doPing - Too late to send ping " + ping.id);
       Telemetry.getHistogramById("TELEMETRY_SEND_FAILURE_TYPE").add("eTooLate");
+      Telemetry.getKeyedHistogramById("TELEMETRY_SEND_FAILURE_TYPE_PER_PING").add(ping.type, "eTooLate");
       return Promise.reject();
     }
 
     this._log.trace("_doPing - server: " + this._server + ", persisted: " + isPersisted +
                     ", id: " + id);
 
     const url = this._buildSubmissionURL(ping);
 
@@ -1159,16 +1160,23 @@ var TelemetrySendImpl = {
     let errorhandler = (event) => {
       let failure = event.type;
       if (failure === "error") {
         failure = XHR_ERROR_TYPE[request.errorCode];
       }
 
       TelemetryHealthPing.recordSendFailure(failure);
       Telemetry.getHistogramById("TELEMETRY_SEND_FAILURE_TYPE").add(failure);
+      try {
+    Telemetry.getKeyedHistogramById("TELEMETRY_SEND_FAILURE_TYPE_PER_PING").add(ping.type, failure);
+  } catch (e) {
+    if (e.result != Cr.NS_ERROR_FAILURE) {
+      throw e;
+    }
+  }
 
       this._log.error("_doPing - error making request to " + url + ": " + failure);
       onRequestFinished(false, event);
     };
     request.onerror = errorhandler;
     request.ontimeout = errorhandler;
     request.onabort = errorhandler;
 

--- a/toolkit/components/telemetry/tests/unit/test_TelemetrySend.js
+++ b/toolkit/components/telemetry/tests/unit/test_TelemetrySend.js
@@ -312,17 +312,16 @@ add_task(async function test_backoffTime
   Assert.deepEqual(histSuccess.snapshot().counts, [sendAttempts, 3, 0],
                "Should have recorded sending failure in histograms.");
   Assert.greaterOrEqual(histSendTimeSuccess.snapshot().sum, 0,
                         "Should have recorded sending success in histograms.");
   Assert.equal(histogramValueCount(histSendTimeSuccess.snapshot()), 3,
                "Should have recorded sending success in histograms.");
   Assert.equal(histogramValueCount(histSendTimeFail.snapshot()), sendAttempts,
                "Should have recorded send failure times in histograms.");
-
   // Restore the default ping id generator.
   fakeGeneratePingId(() => TelemetryUtils.generateUUID());
 });
 
 add_task(async function test_discardBigPings() {
   const TEST_PING_TYPE = "test-ping-type";
 
   let histSizeExceeded = Telemetry.getHistogramById("TELEMETRY_PING_SIZE_EXCEEDED_SEND");
@@ -453,16 +452,26 @@ add_task(async function test_tooLateToSe
   // Triggering a shutdown should persist the pings
   await TelemetrySend.shutdown();
   const pendingPings = TelemetryStorage.getPendingPingList();
   Assert.equal(pendingPings.length, 1, "Should have a pending ping in storage");
   Assert.equal(pendingPings[0].id, id, "Should have pended our test's ping");
 
   Assert.equal(Telemetry.getHistogramById("TELEMETRY_SEND_FAILURE_TYPE").snapshot().counts[7], 1,
     "Should have registered the failed attempt to send");
+  try {
+    let histSnapshot = Telemetry.getKeyedHistogramById("TELEMETRY_SEND_FAILURE_TYPE_PER_PING").snapshot();
+    Assert.equal(histSnapshot[pendingPings[0].type].counts[7], 1, "Should have registered the failed attempt to send");
+  } catch (e) {
+    // This throws if the key is not already registered, but that
+    // doesn't matter.
+    if (e.result != Cr.NS_ERROR_FAILURE) {
+      throw e;
+    }
+  }
 
   await TelemetryStorage.reset();
   Assert.equal(TelemetrySend.pendingPingCount, 0, "Should clean up after yourself");
 });
 
 // Test that the current, non-persisted pending pings are properly saved on shutdown.
 add_task(async function test_persistCurrentPingsOnShutdown() {
   const TEST_TYPE = "test-persistCurrentPingsOnShutdown";