Histórico de mensagens sobre url

Bom dia pessoal
Estou importando a SDK da Efi via composer e está dando esse erro: https://repo.packagist.org could not be fully loaded (curl error 6 while downloading https://repo.packagist.org/packages.json: Could not resolve host: repo.packagist.org), package information was loaded from the local cache and may be out of date
Sabem me dizer o q pode ser?

No EFI retorna o erro : {
"nome": "webhook_invalido",
"mensagem": "A URL informada respondeu com o código HTTP 500"
}