Favicon NOT working on Edge

Question

I have a problem with this favicon I generated for a local server php project. It works fine on most browsers (Google Chrome, Mozilla Firefox and Opera) but on Microsoft Edg

Answer 1

Adding Cache-Control:public, max-age=14400 to the http header worked for me. Checked it with IE, Edge, and Chrome on Windows 10 using an ESP8266-12E running Arduino as a web server on a local network. (Haven't tried any Apple or Android-specific support yet). FWIW - Here's part of the html from the root page of my server:

...

and here's a ESP8266/Arduino code snippet for creating the http header in the response and sending the icon data previously stored as a file using SPIFFS.

...
f = SPIFFS.open("/favicon.ico", "r");
if (!f) {
  Serial.println("file open failed");
} else {
  Serial.println("favicon.ico open succeeded...");
  client.println("HTTP/1.1 200 OK");
  client.print("Content-Length:");
  client.println(String(f.size()));
  client.println("Content-Type:image/x-icon");
  client.println("Cache-Control: public, max-age=14400");
  client.println();  // blank line indicates end of header
  while (f.available()) {  // send the binary for the icon
    byte b = f.read();
    client.write(b);
  }
f.close();
...