Yes, favicons typically need to follow certain formats and dimensions to display correctly across all browsers. While you mentioned trying to upload a 64x64 .ico file, most browsers expect favicons to be 16x16 pixels, especially for legacy support.

Here are some key guidelines for favicon dimensions and formats:

1. Standard Dimensions:
   16x16 pixels – Standard for browser tabs.
   32x32 pixels – Sometimes used by newer browsers or when a higher resolution is needed.
   48x48 pixels – Common for shortcut icons.
   64x64 pixels – Not commonly used, but some platforms may accept it for higher resolutions.
2. Formats:
   .ico – The most widely supported format across browsers.
   .png – Also supported by modern browsers, especially for higher resolutions and transparency.
3. Other Considerations:
   Some browsers may require the favicon to be named "favicon.ico" and placed in the root directory of your website.