Using Password grant type for API authentication sometimes returns an "Invalid token server response"

[Rmy5]

We are using the SDK to authenticate with the API (Password grant type). It usually works fine, but regurlarly we are getting an "Invalid token server response" error with an HTML string as response instead of the normal JSON response (the HTML string is the Dailymotion 500 error page "Quelque chose s'est mal passé…" ).