Hello, when i manually input start date and end date, i am able to create an event at google calendar,
however, when i use the expression, it is not working anymore.
May i know if this is because of of the time format?
Hi @Benjamin123, Google Calendar could indeed be rejecting your time format, if everything else works. From looking at Events: insert | Google Calendar | Google for Developers, Google expects RFC3339-formatted values. Values like 2022-01-11T16:59:24.058Z worked fine for me when I tested this:
You could use the Date & Time node to reformat your timestamps, e.g. like so:
Example Workflow
it is still not working initially, but after i delete the existing google calendar node and recreate a new node, it is working … 
thank you