Multiple Jira Cloud API calls in Jira automation

Hi all
I am trying to create 4 sprints using this endpoint with basic auth through Jira Automation rule on cloud using smart values in dates.
1st one succeeds, and the 2nd one fails with 400
All my payloads are the folllwing (with increments on the plusWeeks with each one):

{"name": "{{now.plusWeeks(4).withNextDayOfWeek("MON").format("d MMM")}} - {{now.plusWeeks(4).withNextDayOfWeek("FRI").format("d MMM uuuu")}} spr","startDate": "{{now.plusWeeks(4).withNextDayOfWeek("MON")}}","endDate": "{{now.plusWeeks(4).withNextDayOfWeek("FRI")}}","originBoardId":1,"goal": ""}

Please advise?
Thank you in advance