Hi there,
Sorry to hear that Photoshop is not able to export video. Would you mind telling us the version of Photoshop and the operating system you're working on?
Also, could you please try resetting the preferences of Photoshop and let us know if that helps?
https://helpx.adobe.com/photoshop/using/preferences.html
Note: Make sure that you back up all your custom presets, brushes & actions before restoring Photoshop's preferences. Migrate presets, actions, and settings
Regards,
Sahil