Try fixup mixed conten error loading widget

backend/dev_nginx.conf

@@ -181,7 +181,10 @@ server {
 
 }
 
-# Convenience reverse proxy for the call.m.localhost domain to yarn dev --host
+# Convenience reverse proxy for the call.m.localhost domain to element call
+# running on the host either via
+# - yarn dev --host or
+# - falling back to http (the element call docker container)
 server {
     listen                  80;
     listen                  [::]:80;
@@ -197,7 +200,7 @@ server {
     ssl_certificate         /root/ssl/cert.pem;
     ssl_certificate_key     /root/ssl/key.pem;
 
-
+    # 1. Attempt HTTPS first
     location ^~ / {
 
       proxy_set_header Host $host;
@@ -208,8 +211,23 @@ server {
       proxy_pass https://host.docker.internal:3000;
       proxy_ssl_verify              off;
 
+      # 2. Redirect specific errors (e.g., 502 Bad Gateway  or 504 Timeout)
+      # to the named fallback location
+      error_page 502 503 504 = @http_fallback;
+
     }
 
+    # 3. Fallback location using HTTP
+    location @http_fallback {
+
+      proxy_set_header Host $host;
+      proxy_set_header X-Real-IP $remote_addr;
+      proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+      proxy_set_header X-Forwarded-Proto $scheme;
+
+      proxy_pass http://host.docker.internal:8080;
+
+    }
     error_page   500 502 503 504  /50x.html;
 
 }

playwright/widget/test-helpers.ts

@@ -248,7 +248,7 @@ export class TestHelpers {
           "Developer.elementCallUrl",
           null,
           "device",
-          "http://localhost:8080/room",
+          "https://call.m.localhost/room",
         );
       });
     } else {