REST API v3 - Issue creating a New Project Version

Hey mates! Hope your are doing well.

I’m creating a new integration with Atlassian and Jira. While doing this a noticed that the endpoint Create New Version isn’t working as expected.

Using your example as template

curl --request POST \
–url ‘https://MY_DOMAIN.atlassian.net/rest/api/3/version’ \
–user ‘USER:TOKEN’ \
–header ‘Accept: application/json’ \
–header ‘Content-Type: application/json’ \
–data ‘{
“archived”: false,
“description”: “An excellent version”,
“name”: “New Version 1”,
“projectId”: EXISTING_PROJECT_ID,
“releaseDate”: “2010-07-06”,
“released”: true
}’

I keep getting

{“errorMessages”:[“Project with key ‘null’ either does not exist or you do not have permission to create versions in it.”],“errors”:{}}

Either I use project field or not the error still the same.

Please can you help me? Thanks in advance.