diff --git a/features/nanostack/mbed-mesh-api/source/wisun_tasklet.c b/features/nanostack/mbed-mesh-api/source/wisun_tasklet.c
index 593b9eefe7..81cbafe0bd 100644
--- a/features/nanostack/mbed-mesh-api/source/wisun_tasklet.c
+++ b/features/nanostack/mbed-mesh-api/source/wisun_tasklet.c
@@ -290,6 +290,7 @@ static void wisun_tasklet_configure_and_connect_to_network(void)
 #else
     trusted_cert.cert_len = strlen((const char *) MBED_CONF_MBED_MESH_API_ROOT_CERTIFICATE) + 1;
 #endif
+    arm_network_trusted_certificates_remove();
     arm_network_trusted_certificate_add((const arm_certificate_entry_s *)&trusted_cert);
 
     arm_certificate_entry_s own_cert = {
@@ -308,6 +309,7 @@ static void wisun_tasklet_configure_and_connect_to_network(void)
 #else
     own_cert.key_len = strlen((const char *) MBED_CONF_MBED_MESH_API_OWN_CERTIFICATE_KEY) + 1;
 #endif
+    arm_network_own_certificates_remove();
     arm_network_own_certificate_add((const arm_certificate_entry_s *)&own_cert);
 #endif