diff --git a/common/cpp/CMakeLists.txt b/common/cpp/CMakeLists.txt
index c55ea7c5316671bfda98130a3fa8383517d5a579..b8ff069c4e0c3dae6784283c97a5485a08e55e22 100644
--- a/common/cpp/CMakeLists.txt
+++ b/common/cpp/CMakeLists.txt
@@ -8,7 +8,9 @@ add_subdirectory(src/data_structs)
 
 add_subdirectory(src/version)
 
-add_subdirectory(src/kafka_client)
+if (NOT BUILD_CLIENTS_ONLY)
+    add_subdirectory(src/kafka_client)
+endif()
 
 add_subdirectory(src/http_client)
 
diff --git a/common/cpp/include/asapo/common/error.tpp b/common/cpp/include/asapo/common/error.tpp
index 931abd205bd37b67dc2c2f017cc5ee9e37721224..3c2c90a662aa8e2f4397e545f93198615c75a15c 100644
--- a/common/cpp/include/asapo/common/error.tpp
+++ b/common/cpp/include/asapo/common/error.tpp
@@ -48,7 +48,7 @@ std::string ServiceError<ServiceErrorType>::ExplainPretty(uint8_t shift) const n
     }
     if (cause_err_ != nullptr) {
         err += "\n" + base_shift + shift_s + "caused by: ";
-        err += "\n" + base_shift + shift_s + cause_err_->ExplainPretty(shift + 2);
+        err += "\n" + base_shift + shift_s + cause_err_->ExplainPretty(static_cast<uint8_t>(shift + 2));
     }
     return err;
 }