Describe the problem/error/question
I’m building an n8n workflow to reschedule Google Calendar events.
Update Event consistently returns 400 Bad Request when using dynamically generated date/time values (especially with specific times), even though the values are valid and previews look correct.
The event ID is valid and there are no whitespace issues.
I previously saw the same behavior with Get Many Events, where only $now-based expressions worked reliably and any dynamically generated date/time values caused 400 errors at runtime.
The input for google calendar is frrom my ai agent, but the input is right.
What is the error message (if any)?
Like i said its the error 400 Bad request.
Please share your workflow
Share the output returned by the last node
[
{
“output”:{
“action”:“continue”,
“customer_name”:“John Doe”,
“existing_date”:“2026-01-10”,
“existing_time”:“14:00”,
“requested_date”:“2026-01-12”,
“requested_time”:“16:30”,
“requested_window”:“”,
“missing_existing_evidence”:“false”,
“missing_requested_schedule”:“false”,
“missing_requested_date”:“false”,
“missing_requested_time”:“false”,
“missing_requested_window”:“true”,
“internal_note”:“All necessary information for rescheduling is present.”
},
“gefunden_id”:“3m8kbgbdvdj7rgvukmnbocco5u”,
“newStart”:“2026-01-12T16:30:00+01:00”,
“newEnd”:“2026-01-12T17:15:00+01:00”
}]
Information on your n8n setup
- **n8n version:**[email protected]
- Database (default: SQLite):no database
- n8n EXECUTIONS_PROCESS setting (default: own, main):default
- Running n8n via (Docker, npm, n8n cloud, desktop app):n8n cloud
- Operating system:windows 11