Trying to click post button after video upload (.mp4) on X gives message "Your video file could not be processed."

[sachi-gkp]

Describe the bug
Trying to click post button after video upload (.mp4) on X gives message "Your video file could not be processed."

To Reproduce
Steps to reproduce the behavior:

1. Go to 'https://x.com/home'
2. Click on 'Post'
3. Attach Media file
4. Click Post button

Environment
Mac OS Sequoia v15.5
Firefox Version 140.0.4, Build ID 20250707120347

HAR file
x.com_live_pipeline_events_Archive [25-07-21 14-14-09].har.zip