The problem

Sadly I can't add my company Office365 calendar via ICS file into Home Assistant. I get the error "Invalid .ics file"
See error message below. I anonymized my ICS URL.

The error message mentioned some wrong timezone, but the timezone seems to be set correctly. Sorry for my German screenshot

I can import the ICS file from my Personal Outlook account without any problem, but the URL is different.
Company O365: https://outlook.office365.com/owa/calendar/XXXX/XXXX/calendar.ics
Private Outlook: https://outlook.live.com/owa/calendar/XXXX/XXXX/XXXX/calendar.ics

Are there any additional information I can provide?

What version of Home Assistant Core has the issue?

core-2025.4.0

What was the last working version of Home Assistant Core?

No response

What type of installation are you running?

Home Assistant OS

Integration causing the issue

Remote Calendar

Link to integration documentation on our website

https://www.home-assistant.io/integrations/remote_calendar

Diagnostics information

No response

Example YAML snippet

Anything in the logs that might be useful for us?

2025-04-03 09:25:57.046 DEBUG (MainThread) [homeassistant.components.remote_calendar.config_flow] User input: {'calendar_name': 'arbeit2', 'url': 'https://outlook.office365.com/owa/calendar/XXXX/XXXX/calendar.ics'}
2025-04-03 09:26:01.597 DEBUG (MainThread) [homeassistant.components.remote_calendar.config_flow] Invalid .ics file: Failed to parse component: 1 validation error for Event
__root__
  IcsTimezoneInfo.__init__() missing 1 required positional argument: 'timezone' (type=type_error)

Additional information

No response