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Calendar is appearing blocked when it shouldn't be

Brian Donnellan 5 Reputation points
2025-11-18T21:36:45.2766667+00:00

Hi,

My calendar on MS Outlook appears blocked. Colleagues can't schedule meetings with me. However, I haven't placed any blocks on my calendar. I have an image of how it appears in Scheduling Assistant. I do have two Outlook calendars for 2 different employers - I'm wondering if this is causing the issue. I've tried all afternoon to troubleshoot this through gpt to no success. As you will notice from the image there is a grey block appearing across my calendar indefinitely. How do I remove that block?

Below are my notes from gpt of everything I tried this afternoon to no avail. Thank you for the help!!

Identity & Account Steps

Verified that my home Microsoft 365 organization is my primary employer, not the secondary organization.

Attempted to switch organizational context inside Outlook and Microsoft Account pages.

Used the Microsoft "Pick an account" screen and chose “Forget” on old/duplicate accounts.

Fully signed out of Microsoft 365 accounts and re-authenticated.

Confirmed I have guest access to the secondary organization but primary identity belongs to another tenant.

Browser & Cache Steps

Cleared browser cache and cookies completely.

Tried using multiple browsers (Chrome, Safari).

Verified that third-party cookies are enabled.

Restarted browser after clearing cache.

Outlook Web App (OWA) Calendar Configuration

Confirmed correct time zone (Eastern Time) in Calendar → View settings.

Verified that “Add a global calendar” is disabled.

Checked “Shared calendars” settings — only default “Can view when I’m busy” is enabled.

Reset shared calendar publishing links.

Verified “Accounts” under Calendar settings — no personal accounts linked.

Checked “Work hours and location” for any anomalies.

Ensured the correct calendar is selected under “My calendars.”

Scheduling Assistant Behavior

Created multiple test events using the Scheduling Assistant.

Confirmed that my own availability appears as “Unknown” for all future times.

Verified that this issue persists regardless of browser or cache resets.

Verified that other calendars appear correctly — only my own free/busy is impacted.

Identity Isolation

Logged out across all Microsoft services using: https://login.microsoftonline.com/logout.srf

Re-logged into Outlook via both:

My primary employer’s account

My secondary organization’s account

Observed that when logged into the secondary tenant, my primary calendar shows Unknown availability.

  • Recognized this may be caused by cross-tenant free/busy visibility issues.

    Identity & Account Steps

  • Verified that my home Microsoft 365 organization is my primary employer, not the secondary organization.
  • Attempted to switch organizational context inside Outlook and Microsoft Account pages.
  • Used the Microsoft "Pick an account" screen and chose “Forget” on old/duplicate accounts.
  • Fully signed out of Microsoft 365 accounts and re-authenticated.
  • Confirmed I have guest access to the secondary organization but primary identity belongs to another tenant.

    Browser & Cache Steps

  • Cleared browser cache and cookies completely.
  • Tried using multiple browsers (Chrome, Safari).
  • Verified that third-party cookies are enabled.
  • Restarted browser after clearing cache.

    Outlook Web App (OWA) Calendar Configuration

  • Confirmed correct time zone (Eastern Time) in Calendar → View settings.
  • Verified that “Add a global calendar” is disabled.
  • Checked “Shared calendars” settings — only default “Can view when I’m busy” is enabled.
  • Reset shared calendar publishing links.
  • Verified “Accounts” under Calendar settings — no personal accounts linked.
  • Checked “Work hours and location” for any anomalies.
  • Ensured the correct calendar is selected under “My calendars.”

    Scheduling Assistant Behavior

  • Created multiple test events using the Scheduling Assistant.
  • Confirmed that my own availability appears as “Unknown” for all future times.
  • Verified that this issue persists regardless of browser or cache resets.
  • Verified that other calendars appear correctly — only my own free/busy is impacted.

    Identity Isolation

    • Logged out across all Microsoft services using:
      https://login.microsoftonline.com/logout.srf
    • Re-logged into Outlook via both:
    • My primary employer’s account
    • My secondary organization’s account
    • Observed that when logged into the secondary tenant, my primary calendar shows Unknown availability.
    • Recognized this may be caused by cross-tenant free/busy visibility issues.
    User's image
Outlook | Web | Outlook on the web for business | Settings

1 answer

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  1. Sophie N 8,600 Reputation points Microsoft External Staff Moderator
    2025-11-19T04:22:55.3166667+00:00

    Dear @Brian Donnellan,

    Thank you for reaching out to the Microsoft Q&A community. Based on your description, the issue where your calendar appears blocked and shows “Unknown” availability is typically caused by cross-tenant free/busy sharing settings when you have accounts from two different Microsoft 365 organizations. 

    To help me narrow down the cause, could you please provide the following details?  

    1. Are you using New Outlook or Classic Outlook (desktop app)? 
    2. Does this issue occur in Outlook on the Web? 
    3. Are you signed in to multiple Microsoft 365 accounts (for example, from different organizations) at the same time? 
    4. Is your calendar shared with at least "Can view when I'm busy" permission? 
    5. Are you using a multi-user or hybrid environment? 
    6. Are you a user or admin for your organization? 

    In the meantime, please try the following official troubleshooting steps which usually resolve issues with basic issues: 

    Step 1: Verify organization relationship settings 

    • Your IT admin needs to configure an Organization Relationship in Exchange Online between the two tenants. 
    • This allows free/busy information to be shared across organizations. 

    Detailed steps: Create an organization relationship in Exchange Online | Microsoft Learn 

    Step 2: Enable calendar sharing policies 

    • Ensure external sharing is enabled for calendars in both tenants. 

    Reference: Sharing in Exchange Online | Microsoft Learn 

    Step 3: Allow time for propagation 

    • After configuration, changes may take up to 24 hours to reflect. 

    If you are not an admin, please share this information with your IT department so they can apply the necessary settings. 

    For more details on inter-tenant collaboration, see: Microsoft 365 inter-tenant collaboration - Microsoft 365 Enterprise | Microsoft Learn 

    Please let me know if you need further assistance or if the issue persists after these steps. 

    If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".   

    Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.

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