Uploading docs to obtain social security number at Depotdoc

I am an American citizen with a long term visa (spousal visa). I have been working in France for a technology firm since December 2022. I have yet to obtain a social security number and was told to go to https://cpam06.depotdoc.fr/assure/depot to upload my documents. I was instructed to use thirteen "0"'s in the field for "Numéro de sécurité sociale avec la clef *" since I do not have a social security number. , However, after selecting the docs to upload (and all other fields filled out), I got an error indicating the number is invalid. I called again and this time was instructed to enter thirteen "9"s. This also resulted in the same error. I figure there is a special number to put in here but not sure if I need to enter it in a specific format (I entered "0000000000000" and "9999999999999") or if there is a different special number to use. Thank you much for your prompt response.