diff --git a/daemon/src/sip/tlsvalidation.c b/daemon/src/sip/tlsvalidation.c
index 58c2bbb934e8ebc562b767093b94c4cb3e564e0c..8800ed81c049feebeed33429a6aa4e9162c1d79e 100644
--- a/daemon/src/sip/tlsvalidation.c
+++ b/daemon/src/sip/tlsvalidation.c
@@ -181,6 +181,7 @@ static unsigned char *crypto_cert_read(const char *path, size_t *out_len)
     err = gnutls_x509_crt_export(cert, GNUTLS_X509_FMT_DER, data, out_len);
     if (err != GNUTLS_E_SUCCESS) {
         free(data);
+        data = NULL;
         *out_len = 0;
         ERROR("Certificate %s could not be exported - %s.\n",
               path, gnutls_strerror(err));