Can't use colon in a request body in c#

Question

Hi everyone,

I have at least a response from the API and I think that response is the json is not formatted correctly and this is because I can't use colon in the code and I don't know why...

I put the code below, then, the response from the API hopefully someone will be able to send me a corrected code :)

You can see in the documentation of the API creators that the body is not the same, here more information:

{"retourCertif":{"jsonVersi":"01.00","listErr":[{"id":"JW00B999200E","mess":"La syntaxe JSON n'est pas formatée correctement.","codRetour":"91"},{"id":"JW00B999999E","mess":"Veuillez contacter votre détaillant."}]}}

When I run the program, I receive this response from the API, and the description of the errors from the API creators.

Translation: The JSON syntax is not formatted correctly, message JW00B999200E

Thanks