Sometimes you may encounter problems when creating a JIRA issue using the create JIRA button only for a particular vulnerability. While you are successfully able to create a JIRA issue for other issues in the project.
This could be due to the fact that Snyk includes some example exploit code when adding to the Jira description, and when submitted the request is blocked by WAF (web application firewall) and thus the request cannot be completed. The example exploit code is never actually executed so it is safe to have in the JIRA description, but the WAF is not aware of the fact this it is an example, and thus blocks the request.
The solution is usually to remove the example code from the JIRA description and try again.