Unable to set assignee while creating the jira issue REST API v2.

[Pravash Raj Upreti]

We have Jira automation for several recurring tasks. The API to create an issue was working and able to set the assignee. But the recent tickets are creating with Unassigned. 

Python library is used for creating the issue. https://jira.readthedocs.io/en/latest/index.html

key set on creating an issue

assignee={name: <user name> }