diff --git a/modules/audio_device/ios/audio_device_ios.mm b/modules/audio_device/ios/audio_device_ios.mm
index f7a3934bba..5dd816a92f 100644
--- a/modules/audio_device/ios/audio_device_ios.mm
+++ b/modules/audio_device/ios/audio_device_ios.mm
@@ -643,10 +643,10 @@ void AudioDeviceIOS::UpdateAudioDeviceBuffer() {
   // AttachAudioBuffer() is called at construction by the main class but check
   // just in case.
   RTC_DCHECK(audio_device_buffer_) << "AttachAudioBuffer must be called first";
-  RTC_CHECK_GT(playout_parameters_.sample_rate(), 0);
-  RTC_CHECK_GT(record_parameters_.sample_rate(), 0);
-  RTC_CHECK_EQ(playout_parameters_.channels(), 1);
-  RTC_CHECK_EQ(record_parameters_.channels(), 1);
+  RTC_DCHECK_GT(playout_parameters_.sample_rate(), 0);
+  RTC_DCHECK_GT(record_parameters_.sample_rate(), 0);
+  RTC_DCHECK_EQ(playout_parameters_.channels(), 1);
+  RTC_DCHECK_EQ(record_parameters_.channels(), 1);
   // Inform the audio device buffer (ADB) about the new audio format.
   audio_device_buffer_->SetPlayoutSampleRate(playout_parameters_.sample_rate());
   audio_device_buffer_->SetPlayoutChannels(playout_parameters_.channels());
@@ -860,16 +860,22 @@ bool AudioDeviceIOS::InitPlayOrRecord() {
     return false;
   }
 
-  // If we are ready to play or record, initialize the audio unit.
+  // If we are ready to play or record, and if the audio session can be
+  // configured, then initialize the audio unit.
   if (session.canPlayOrRecord) {
-    ConfigureAudioSession();
+    if (!ConfigureAudioSession()) {
+      // One possible reason for failure is if an attempt was made to use the
+      // audio session during or after a Media Services failure.
+      // See AVAudioSessionErrorCodeMediaServicesFailed for details.
+      [session unlockForConfiguration];
+      return false;
+    }
     SetupAudioBuffersForActiveAudioSession();
     audio_unit_->Initialize(playout_parameters_.sample_rate());
   }
 
   // Release the lock.
   [session unlockForConfiguration];
-
   return true;
 }