diff --git a/src/core/ddsc/src/dds_psmx.c b/src/core/ddsc/src/dds_psmx.c
index 7f613984d9..20f52beed7 100644
--- a/src/core/ddsc/src/dds_psmx.c
+++ b/src/core/ddsc/src/dds_psmx.c
@@ -327,40 +327,32 @@ static dds_return_t psmx_instance_load (const struct ddsi_domaingv *gv, const st
   return ret;
 }
 
-static int compare_psmx_prio (const void *va, const void *vb)
-{
-  const struct dds_psmx *psmx1 = va;
-  const struct dds_psmx *psmx2 = vb;
-  return (psmx1->priority == psmx2->priority) ? 0 : ((psmx1->priority < psmx2->priority) ? 1 : -1);
-}
-
 dds_return_t dds_pubsub_message_exchange_init (const struct ddsi_domaingv *gv, struct dds_domain *domain)
 {
   dds_return_t ret = DDS_RETCODE_OK;
   if (gv->config.psmx_instances != NULL)
   {
     struct ddsi_config_psmx_listelem *iface = gv->config.psmx_instances;
-    while (iface && domain->psmx_instances.length < DDS_MAX_PSMX_INSTANCES)
-    {
-      GVLOG(DDS_LC_INFO, "Loading PSMX instances %s\n", iface->cfg.name);
-      struct dds_psmx *psmx = NULL;
-      ddsrt_dynlib_t lib_handle;
-      if (psmx_instance_load (gv, &iface->cfg, &psmx, &lib_handle) == DDS_RETCODE_OK)
-      {
-        domain->psmx_instances.instances[domain->psmx_instances.length] = psmx;
-        domain->psmx_instances.lib_handles[domain->psmx_instances.length] = lib_handle;
-        domain->psmx_instances.length++;
-      }
-      else
-      {
-        GVERROR ("error loading PSMX instance \"%s\"\n", iface->cfg.name);
-        ret = DDS_RETCODE_ERROR;
-        break;
+    if ( iface != NULL ) {
+      if ( iface->next != NULL ) {
+        ret = DDS_RETCODE_UNSUPPORTED; // Only one psmx interface is supported.
+      }else{
+        GVLOG(DDS_LC_INFO, "Loading PSMX instances %s\n", iface->cfg.name);
+        struct dds_psmx *psmx = NULL;
+        ddsrt_dynlib_t lib_handle;
+        if (psmx_instance_load (gv, &iface->cfg, &psmx, &lib_handle) == DDS_RETCODE_OK)
+        {
+          domain->psmx_instances.instances[domain->psmx_instances.length] = psmx;
+          domain->psmx_instances.lib_handles[domain->psmx_instances.length] = lib_handle;
+          domain->psmx_instances.length++;
+        }
+        else
+        {
+          GVERROR ("error loading PSMX instance \"%s\"\n", iface->cfg.name);
+          ret = DDS_RETCODE_ERROR;
+        }
       }
-      iface = iface->next;
     }
-
-    qsort (domain->psmx_instances.instances, domain->psmx_instances.length, sizeof (*domain->psmx_instances.instances), compare_psmx_prio);
   }
   return ret;
 }
diff --git a/src/core/ddsc/tests/CMakeLists.txt b/src/core/ddsc/tests/CMakeLists.txt
index c10d9e9a30..b54e40ad0f 100644
--- a/src/core/ddsc/tests/CMakeLists.txt
+++ b/src/core/ddsc/tests/CMakeLists.txt
@@ -159,15 +159,10 @@ if(ENABLE_QOS_PROVIDER)
 endif()
 
 # PSMX dummy implementation for interface testing
-set(
-  psmx_dummy_sources
-  "psmx_dummy_impl.c"
-  "psmx_dummy_impl.h"
-)
 if(BUILD_SHARED_LIBS)
-  add_library(psmx_dummy SHARED ${psmx_dummy_sources})
+  add_library(psmx_dummy SHARED "psmx_dummy_impl.c")
 else()
-  add_library(psmx_dummy OBJECT ${psmx_dummy_sources})
+  add_library(psmx_dummy OBJECT "psmx_dummy_impl.c")
   set_property(GLOBAL APPEND PROPERTY cdds_plugin_list psmx_dummy)
   set_property(GLOBAL PROPERTY psmx_dummy_symbols dummy_create_psmx)
 endif()
@@ -199,6 +194,7 @@ add_cunit_executable(cunit_ddsc ${ddsc_test_sources})
 target_include_directories(
   cunit_ddsc PRIVATE
   "$<BUILD_INTERFACE:${CMAKE_BINARY_DIR}/src/include/>"
+  "$<BUILD_INTERFACE:${CMAKE_CURRENT_BINARY_DIR}/include>"
   "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../../ddsc/src>"
   "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../../ddsi/include>"
   "$<BUILD_INTERFACE:${CMAKE_CURRENT_SOURCE_DIR}/../../ddsi/src>"
diff --git a/src/core/ddsc/tests/psmx_dummy_public.h b/src/core/ddsc/tests/psmx_dummy_public.h
index 3037900726..176ec63f4a 100644
--- a/src/core/ddsc/tests/psmx_dummy_public.h
+++ b/src/core/ddsc/tests/psmx_dummy_public.h
@@ -12,6 +12,8 @@
 #ifndef PSMX_DUMMY_PUBLIC_H
 #define PSMX_DUMMY_PUBLIC_H
 
+#include "dds/psmx_dummy/export.h"
+
 #if defined (__cplusplus)
 extern "C" {
 #endif
@@ -58,9 +60,9 @@ typedef struct dummy_mockstats_s{
   dds_loaned_sample_t* write_rcv_loan;
 }dummy_mockstats_t;
 
-DDS_EXPORT dummy_mockstats_t* dummy_mockstats_get_ptr(void);
-DDS_EXPORT void dummy_topics_alloc(dummy_mockstats_t* mockstats, size_t topics_capacity);
-DDS_EXPORT void dummy_endpoints_alloc(dummy_mockstats_t* mockstats, size_t endpoints_capacity);
+PSMX_DUMMY_EXPORT dummy_mockstats_t* dummy_mockstats_get_ptr(void);
+PSMX_DUMMY_EXPORT void dummy_topics_alloc(dummy_mockstats_t* mockstats, size_t topics_capacity);
+PSMX_DUMMY_EXPORT void dummy_endpoints_alloc(dummy_mockstats_t* mockstats, size_t endpoints_capacity);
 
 #if defined (__cplusplus)
 }
diff --git a/src/core/ddsc/tests/psmxif.c b/src/core/ddsc/tests/psmxif.c
index f5c98ff9e0..cdccc554a0 100644
--- a/src/core/ddsc/tests/psmxif.c
+++ b/src/core/ddsc/tests/psmxif.c
@@ -149,6 +149,7 @@ CU_Test(ddsc_psmxif, config_multiple_psmx)
     configstr_in = ddsrt_expand_envvars(configstr, domainId);
   }
   const dds_entity_t domain = dds_create_domain (domainId, configstr_in);
+  ddsrt_free(configstr_in);
   CU_ASSERT_FATAL(domain <= 0);
 }