diff --git a/src/openvpn/ssl_mbedtls.c b/src/openvpn/ssl_mbedtls.c
index 83fca78..3440319 100644
--- a/src/openvpn/ssl_mbedtls.c
+++ b/src/openvpn/ssl_mbedtls.c
@@ -466,10 +466,14 @@
 
     if (cert_inline)
     {
+        if (!cert_file)
+        {
+            msg(M_FATAL, "Cannot load inline certificate: NULL");
+        }
         if (!mbed_ok(mbedtls_x509_crt_parse(ctx->crt_chain, (const unsigned char *)cert_file,
                                             strlen(cert_file) + 1)))
         {
-            msg(M_FATAL, "Cannot load inline certificate file");
+            msg(M_FATAL, "Cannot load inline certificate");
         }
     }
     else