Hi there, I'm John, a fellow Microsoft user like you.
I understand you're having issues converting the MP4 file to a GIF. I'm here to help.
This behavior is expected in Windows. MP4 and GIF files have fundamentally different structures and codecs. An MP4 file is designed to store video and audio data, while a GIF is optimized for storing a series of still images. Simply changing the file extension doesn't modify the actual data, so the file won’t be recognized as a valid GIF and will likely fail to play or upload properly.
To convert an MP4 to a GIF, you'll need to use a dedicated conversion tool online. These tools can process the MP4 data and re-encode it into a GIF format that can be played or uploaded correctly. Alternatively you can use Microsoft Clipchamp https://clipchamp.com/en/blog/convert-video-gif/
Should you need further information please let me know.
Regards,
John J.D.