Not allowed to translate a message
Usually this occurs when the resource to translate contain raw HTML and the HTML elements or some of its attributes are not completely safe, or is not checked automatically as being safe, or uses an uncommon encoding and is not fully plain-text or the encoding could be used to bypass a HTML security).
You need to specify the link to the message you want to translate, and the language code.
Then submit your translation proposal in a thread posted here, asking for an admininstrator to submit it for you. Your message will also help project maintainers find a better solution to make these resources more easily translatable without the possible security issue. In some projects, the doc page ("/qqq") shows a contact address or link that you can use (possibly on a repository or bug tracker).