Planner - Unable to add plan to Outlook calendar

As this forum is a public platform, we’ve taken steps to help protect your privacy by removing your organization’s domain name from your message. To ensure your data remains secure, we kindly recommend avoiding the inclusion of personal or organizational details such as domain names or screenshots with sensitive information in future posts.  

Hi @Schauls Stacy, 

Good day, and I appreciate how clearly you detailed your concern. You are encountering a Publish was unsuccessful error accompanied by a Correlation ID when attempting to generate an iCal link for your Planner. 

This error typically occurs when organizational security policies restrict sharing calendar data externally. Additionally, insufficient plan permissions or stale browser cache tokens can block the system from generating the required public link. The Correlation ID you provided is a specific server log tracker indicating that the background process was actively denied by one of these factors. 

Here are three advanced step by step solutions tailored to your situation to fix this issue: 

1/ Confirm the plan is eligible and publish the iCalendar feed as the plan owner 

• Open the plan in Microsoft Planner and open the plan menu (the chevron next to the plan name).  
• Select “Add plan to Outlook calendar”; if you do not see this option, confirm you are the plan owner for this plan.  
• Select “Publish, share with anyone” to publish the plan to an iCalendar feed, then select “Add to Outlook” to continue the setup in Outlook.  
• In Outlook, use “Subscribe from web”, optionally rename the calendar, then select “Import”.  

2/ Refresh the feed by turning publishing off, then publishing again 

• Return to the plan’s calendar publishing settings using the same plan menu path used for calendar sync.  
• Select “Don’t publish, keep private” to turn off the existing iCalendar feed setting for that plan.  
• Open the publishing settings again and select “Publish, share with anyone” to generate a fresh iCalendar feed.  
• Select “Add to Outlook” and complete the import via “Subscribe from web” in Outlook.  
• Reference: See your Planner schedule in Outlook calendar - Microsoft Support 

3/ If the calendar subscription step is the blocker, add it through Outlook on the web 

• Sign in to Outlook on the web and switch to Calendar. 
• Select “Add calendar”, then select “From internet” (or “Subscribe from web”, depending on the experience shown). 
• Paste the iCalendar link and select “Save” to create the subscription.  
• If the subscription was added through Outlook on the web, updates are managed by Exchange and typically sync about every four hours. 
• Reference: Can't add an Internet calendar - Outlook | Microsoft Learn 

4/ Clear stale authentication tokens 

• Open your web browser and completely clear your cookies and cached site data for all Microsoft domains. 
• Alternatively, open an InPrivate or Incognito browsing window. 
• Log into Planner anew and attempt the publishing process again to force the system to generate a fresh session token. 

5/ Verify tenant sync settings with your IT administrator 

• Contact your local Microsoft 365 administrator. 
• Request them to navigate to the Microsoft 365 Admin Center. 
• They need to access Settings, then Org Settings, and select Planner. 
• Ensure the option to allow your organization to sync Planner to an Outlook calendar is active. 
• If the issue continues after these steps, please contact your organization’s IT administrator to review your account configuration or you can ask your IT administrator to submit a support request directly to Microsoft Support team.        

They can raise a support ticket by visiting: Get support - Microsoft 365 admin | Microsoft Learn  

As community moderators, we appreciate your understanding that our access to internal development details is limited. Our primary role is to guide users toward the appropriate resources and support channels. While we may not have visibility into deeper backend analysis, we’ll continue doing our best to support you within the scope of our responsibilities.      

I hope this information is helpful. Please follow these steps and let me know if it works for you. If you have any updates regarding the issue, please feel free to share them with me.        

Thank you for your patience and your understanding. I look forward to continuing the conversation.  

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.

The error occurs while publishing the Planner plan’s iCalendar feed, which is required before Outlook can subscribe to it. The available information only documents how the feature works when publishing succeeds; it does not provide specific causes or fixes for a failed “Publish was unsuccessful, please try again” error.

To proceed, the plan owner must successfully publish the plan to an iCalendar feed and obtain a valid iCalendar link. Once publishing works, the plan can be added to Outlook by choosing Add to Outlook and completing the Subscribe from web step, or by manually subscribing to the iCalendar URL in Outlook.

If publishing continues to fail, the issue must be escalated through Microsoft 365 support with the correlation ID and timestamp so that backend logs can be checked.

References:

• See your Planner schedule in Outlook calendar
• Use a screen reader to add Microsoft Planner tasks to a calendar