diff --git a/src/AgApiClient.h b/src/AgApiClient.h
index 167a4eb..9f39ceb 100644
--- a/src/AgApiClient.h
+++ b/src/AgApiClient.h
@@ -20,7 +20,12 @@ class AgApiClient : public PrintLog {
 private:
   Configuration &config;
   AirGradient *ag;
+#ifdef ESP8266
+  // ESP8266 not support HTTPS
+  String apiRoot = "http://hw.airgradient.com";
+#else
   String apiRoot = "https://hw.airgradient.com";
+#endif
 
   bool apiRootChanged = false; // Indicate if setApiRoot() is called
   bool getConfigFailed;