diff --git a/test-proxy/src/main/java/com/google/cloud/bigtable/testproxy/CbtTestProxy.java b/test-proxy/src/main/java/com/google/cloud/bigtable/testproxy/CbtTestProxy.java
index 759f1de867..fd7588675b 100644
--- a/test-proxy/src/main/java/com/google/cloud/bigtable/testproxy/CbtTestProxy.java
+++ b/test-proxy/src/main/java/com/google/cloud/bigtable/testproxy/CbtTestProxy.java
@@ -828,6 +828,9 @@ private InstantiatingGrpcChannelProvider getTransportChannel(
               public ManagedChannelBuilder apply(ManagedChannelBuilder input) {
                 NettyChannelBuilder channelBuilder = (NettyChannelBuilder) input;
 
+                // The default replaces long (several KiB) error messages with "http2 exception"
+                channelBuilder.maxInboundMetadataSize(Integer.MAX_VALUE);
+
                 if (sslContext != null) {
                   channelBuilder.sslContext(sslContext);
                 }