diff --git a/include/mscclpp/proxy_channel.hpp b/include/mscclpp/proxy_channel.hpp
index c8719aca..d7566db0 100644
--- a/include/mscclpp/proxy_channel.hpp
+++ b/include/mscclpp/proxy_channel.hpp
@@ -41,6 +41,9 @@ class ProxyService : public BaseProxyService {
   /// @return The ID of the semaphore.
   SemaphoreId addSemaphore(std::shared_ptr<Connection> connection);
 
+  /// Add a pitch pair to the proxy service.
+  /// @param id The ID of the semaphore.
+  /// @param pitch The pitch pair.
   void addPitch(SemaphoreId id, std::pair<uint64_t, uint64_t> pitch);
 
   /// Register a memory region with the proxy service.
diff --git a/src/proxy_channel.cc b/src/proxy_channel.cc
index 56470a0b..a06eea26 100644
--- a/src/proxy_channel.cc
+++ b/src/proxy_channel.cc
@@ -67,7 +67,7 @@ ProxyHandlerResult ProxyService::handleTrigger(ProxyTrigger triggerRaw) {
     RegisteredMemory& dst = memories_[trigger->fields.dstMemoryId];
     RegisteredMemory& src = memories_[trigger->fields.srcMemoryId];
     if (trigger->fields2D.multiDimensionFlag) {
-      std::pair<uint64_t, uint64_t>& pitch = pitches_[trigger->fields.chanId];
+      std::pair<uint64_t, uint64_t>& pitch = pitches_.at(trigger->fields.chanId);
       semaphore->connection()->write2D(dst, trigger->fields.dstOffset, pitch.first, src, trigger->fields.srcOffset,
                                        pitch.second, trigger->fields2D.width, trigger->fields2D.height);
     } else {