Based on the size and number of files in your build, it looks like the deploy is not able to complete in 15 minutes, which is the deploy time cutoff for our free product. There’s a bit more information in this response:
Some things you could look into would be:
storing your large files externally (like an S3 bucket) and linking to them in your site so your site doesn’t have to incorporate them into every build and deploy
checking out Netlify Large Media