How big is it? Usually it’s because it’s over the limit. 

 What’s the limit? 

 please charge your phone isa 😭😂

what size is the video file? 

 HHAHAHAHA is my phone the issue??? 

 DM me on telegram, we’ll figure it out 

 Restart your app and try again 

 I had the same problem. Figured it was an issue with nostr.build because when I switched to nostrimg.com it worked. Settings > Appearance and filters > Image uploader 

 It might be too big, try another uploader or you could purchase a nostr.build acct 

 Some problem with your client. 
Try a different client, maybe a web client. 
Or even upload on a third-party upload site and just paste the link to your video on your note. 
Example of third-party site: https://envs.sh/