diff --git a/lib/doh.c b/lib/doh.c
index 027b138e25..64fb54e33a 100644
--- a/lib/doh.c
+++ b/lib/doh.c
@@ -348,10 +348,10 @@ static CURLcode doh_probe_run(struct Curl_easy *data,
 #endif
 #ifndef DEBUGBUILD
   /* enforce HTTPS if not debug */
-  ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTPS);
+  ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, (long)CURLPROTO_HTTPS);
 #else
   /* in debug mode, also allow http */
-  ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, CURLPROTO_HTTP|CURLPROTO_HTTPS);
+  ERROR_CHECK_SETOPT(CURLOPT_PROTOCOLS, (long)CURLPROTO_HTTP|CURLPROTO_HTTPS);
 #endif
   ERROR_CHECK_SETOPT(CURLOPT_TIMEOUT_MS, (long)timeout_ms);
   ERROR_CHECK_SETOPT(CURLOPT_SHARE, (CURLSH *)data->share);