Hi, @javiernuber, and welcome to our Netlify community site.
Would you please send us the URL which references the manifest.webmanifest file?
You can also send this to us the x-nf-request-id for a response for this asset also instead if you like…
You can private message (PM) that to one of our support staff if you prefer and I’ve confirmed that PMs are enabled for your community login. Note, that only one person can see the PM and this will likely mean a slower reply than posting the information publicly. Please feel free to reply to however you prefer though.