diff --git a/quic/core/http/quic_spdy_session.cc b/quic/core/http/quic_spdy_session.cc
index 53ec3cc..a2bb509 100644
--- a/quic/core/http/quic_spdy_session.cc
+++ b/quic/core/http/quic_spdy_session.cc
@@ -402,18 +402,22 @@
       2 * max_inbound_header_list_size_);
 }
 
-void QuicSpdySession::OnDecoderStreamError(QuicStringPiece /*error_message*/) {
+void QuicSpdySession::OnDecoderStreamError(QuicStringPiece error_message) {
   DCHECK(VersionUsesQpack(transport_version()));
 
-  // TODO(112770235): Signal connection error on decoder stream errors.
-  QUIC_NOTREACHED();
+  // TODO(b/124216424): Use HTTP_QPACK_DECODER_STREAM_ERROR.
+  CloseConnectionWithDetails(
+      QUIC_DECOMPRESSION_FAILURE,
+      QuicStrCat("Decoder stream error: ", error_message));
 }
 
-void QuicSpdySession::OnEncoderStreamError(QuicStringPiece /*error_message*/) {
+void QuicSpdySession::OnEncoderStreamError(QuicStringPiece error_message) {
   DCHECK(VersionUsesQpack(transport_version()));
 
-  // TODO(112770235): Signal connection error on encoder stream errors.
-  QUIC_NOTREACHED();
+  // TODO(b/124216424): Use HTTP_QPACK_ENCODER_STREAM_ERROR.
+  CloseConnectionWithDetails(
+      QUIC_DECOMPRESSION_FAILURE,
+      QuicStrCat("Encoder stream error: ", error_message));
 }
 
 void QuicSpdySession::OnStreamHeadersPriority(
diff --git a/quic/core/http/quic_spdy_session_test.cc b/quic/core/http/quic_spdy_session_test.cc
index e5d50b2..f5bab97 100644
--- a/quic/core/http/quic_spdy_session_test.cc
+++ b/quic/core/http/quic_spdy_session_test.cc
@@ -2473,6 +2473,48 @@
       "Received a duplicate QPACK decoder stream: Closing connection.");
 }
 
+TEST_P(QuicSpdySessionTestClient, EncoderStreamError) {
+  if (!VersionUsesQpack(transport_version())) {
+    return;
+  }
+
+  std::string data = QuicTextUtils::HexDecode(
+      "02"    // Encoder stream.
+      "00");  // Duplicate entry 0, but no entries exist.
+
+  QuicStreamId stream_id =
+      GetNthServerInitiatedUnidirectionalStreamId(transport_version(), 0);
+
+  QuicStreamFrame frame(stream_id, /* fin = */ false, /* offset = */ 0, data);
+
+  EXPECT_CALL(
+      *connection_,
+      CloseConnection(QUIC_DECOMPRESSION_FAILURE,
+                      "Encoder stream error: Invalid relative index.", _));
+  session_.OnStreamFrame(frame);
+}
+
+TEST_P(QuicSpdySessionTestClient, DecoderStreamError) {
+  if (!VersionUsesQpack(transport_version())) {
+    return;
+  }
+
+  std::string data = QuicTextUtils::HexDecode(
+      "03"    // Decoder stream.
+      "00");  // Insert Count Increment with forbidden increment value of zero.
+
+  QuicStreamId stream_id =
+      GetNthServerInitiatedUnidirectionalStreamId(transport_version(), 0);
+
+  QuicStreamFrame frame(stream_id, /* fin = */ false, /* offset = */ 0, data);
+
+  EXPECT_CALL(
+      *connection_,
+      CloseConnection(QUIC_DECOMPRESSION_FAILURE,
+                      "Decoder stream error: Invalid increment value 0.", _));
+  session_.OnStreamFrame(frame);
+}
+
 }  // namespace
 }  // namespace test
 }  // namespace quic
diff --git a/quic/tools/quic_simple_client_session.cc b/quic/tools/quic_simple_client_session.cc
index b7743f8..f39d8fa 100644
--- a/quic/tools/quic_simple_client_session.cc
+++ b/quic/tools/quic_simple_client_session.cc
@@ -8,6 +8,27 @@
 
 namespace quic {
 
+QuicSimpleClientSession::QuicSimpleClientSession(
+    const QuicConfig& config,
+    const ParsedQuicVersionVector& supported_versions,
+    QuicConnection* connection,
+    const QuicServerId& server_id,
+    QuicCryptoClientConfig* crypto_config,
+    QuicClientPushPromiseIndex* push_promise_index,
+    bool drop_response_body)
+    : QuicSpdyClientSession(config,
+                            supported_versions,
+                            connection,
+                            server_id,
+                            crypto_config,
+                            push_promise_index),
+      drop_response_body_(drop_response_body) {
+  // Do not use the QPACK dynamic table in tests to avoid flakiness due to the
+  // uncertain order of receiving the SETTINGS frame and sending headers.
+  set_qpack_maximum_dynamic_table_capacity(0);
+  set_qpack_maximum_blocked_streams(0);
+}
+
 std::unique_ptr<QuicSpdyClientStream>
 QuicSimpleClientSession::CreateClientStream() {
   return std::make_unique<QuicSimpleClientStream>(
diff --git a/quic/tools/quic_simple_client_session.h b/quic/tools/quic_simple_client_session.h
index 1a17f3d..0ebca98 100644
--- a/quic/tools/quic_simple_client_session.h
+++ b/quic/tools/quic_simple_client_session.h
@@ -18,14 +18,7 @@
                           const QuicServerId& server_id,
                           QuicCryptoClientConfig* crypto_config,
                           QuicClientPushPromiseIndex* push_promise_index,
-                          bool drop_response_body)
-      : QuicSpdyClientSession(config,
-                              supported_versions,
-                              connection,
-                              server_id,
-                              crypto_config,
-                              push_promise_index),
-        drop_response_body_(drop_response_body) {}
+                          bool drop_response_body);
 
   std::unique_ptr<QuicSpdyClientStream> CreateClientStream() override;
 
diff --git a/quic/tools/quic_simple_server_session.cc b/quic/tools/quic_simple_server_session.cc
index 8298122..1a03ab5 100644
--- a/quic/tools/quic_simple_server_session.cc
+++ b/quic/tools/quic_simple_server_session.cc
@@ -36,6 +36,11 @@
           QuicUtils::GetInvalidStreamId(connection->transport_version())),
       quic_simple_server_backend_(quic_simple_server_backend) {
   DCHECK(quic_simple_server_backend_);
+
+  // Do not use the QPACK dynamic table in tests to avoid flakiness due to the
+  // uncertain order of receiving the SETTINGS frame and sending headers.
+  set_qpack_maximum_dynamic_table_capacity(0);
+  set_qpack_maximum_blocked_streams(0);
 }
 
 QuicSimpleServerSession::~QuicSimpleServerSession() {