Shopify Storefront API getProductMedia - shopify

Question

I tried following the offical Shopify Documentation for retrieving ProductMedia.
My Query looks like this:
query getProductMediaById($id: ID!) {
product(id: $id) {
id
media(first: 10) {
edges {
node {
mediaContentType
alt
...mediaFieldsByType
}
}
}
}
}
fragment mediaFieldsByType on Media {
... on ExternalVideo {
id
embeddedUrl
}
... on MediaImage {
image {
...imageAttributes
}
}
... on Model3d {
sources {
url
mimeType
format
filesize
}
}
... on Video {
sources {
url
mimeType
format
height
width
}
}
}
fragment imageAttributes on Image {
altText
url
}
The only thing where I diverged from the official documentation is to put the image attributes to another fragment for code reuse.
But when I try to execute the query I get the following response:
{
"data": {
"product": {
"__typename": "Product",
"id": "Z2lkOi8vc2hvcGlmeS9Qcm9kdWN0LzY3NjcyOTczMzEzMDU=",
"media": {
"__typename": "MediaConnection",
"edges": [
{
"__typename": "MediaEdge",
"node": {
"__typename": "MediaImage",
"mediaContentType": "IMAGE",
"alt": ""
}
}
]
}
}
},
"loading": false,
"networkStatus": 7
}
Or to put it to words my response doesn't contain any information from the mediaFieldsByType fragment.
Any Idea what I'm doing wrong?