diff --git a/src/apps/relay/acme.c b/src/apps/relay/acme.c
index 81a12fe..3adba31 100644
--- a/src/apps/relay/acme.c
+++ b/src/apps/relay/acme.c
@@ -55,7 +55,7 @@ static int is_acme_req(char *req, size_t len) {
     }
     // finally check for allowed chars
     for (size_t k = GET_ACME_PREFIX_LEN; k < i; k++) {
-      const char c = req[k];
+      const unsigned char c = req[k];
       if ((c > 127) || (A[c] == ' ')) {
         return -3;
       }
diff --git a/src/apps/relay/http_server.c b/src/apps/relay/http_server.c
index 015d1fb..7e0bb52 100644
--- a/src/apps/relay/http_server.c
+++ b/src/apps/relay/http_server.c
@@ -74,7 +74,7 @@ static void write_http_echo(ioa_socket_handle s) {
                TURN_SOFTWARE, strlen(content_http), content_http);
 
       ioa_network_buffer_handle nbh_http = ioa_network_buffer_allocate(s->e);
-      char *data = ioa_network_buffer_data(nbh_http);
+      char *data = (char *)ioa_network_buffer_data(nbh_http);
 
       strcpy(data, data_http);
       ioa_network_buffer_set_size(nbh_http, strlen(data_http));