$ curl -X 'GET' -s -S 'http://localhost:8000/repositories/test-repo-2' -H 'accept: application/json' | jq
{
  "_id": "689654c4f845f50c7d09e63a",
  "key": "test-repo-2",
  ...
}

$ curl -X 'GET' -s -S 'http://localhost:8000/repositories/rhaiis%2Fcontainers' -H 'accept: application/json'
{"detail":"Not Found"}

The document exists:
$ curl -X 'GET' -s -S 'http://localhost:8000/repositories' -H 'accept: application/json' | jq '.[] | select(.key == "rhaiis/containers")'
{
  "_id": "68a5a11943e254abe6d5e143",
  "key": "rhaiis/containers",
  ...
}