Unexpected error occurred – A generic error message indicating an unexpected issue

Power Automate is widely used for automating workflows across Microsoft 365, SharePoint, Dynamics 365, and external APIs. However, sometimes users encounter the following error:

“Unexpected error occurred – A generic error message indicating an unexpected issue.”

This error message is vague and does not specify the exact cause of failure, making troubleshooting difficult. However, by following a systematic approach, you can identify and resolve the issue.

---

2. Causes of the “Unexpected Error Occurred” Message

Since this is a generic error, it can result from multiple factors:

1. Temporary Service Issues – Microsoft services (e.g., SharePoint, Dataverse, Outlook) might be experiencing downtime or high traffic.
2. Flow Corruption – The flow may have a structural issue, causing it to fail unexpectedly.
3. Invalid or Expired Connections – If an API key, authentication token, or OAuth connection is invalid or expired, the flow might fail.
4. Data Type Mismatch – An action expecting a certain data type (e.g., integer) may receive an incompatible type (e.g., string).
5. Incorrect Expressions or Parameters – Syntax errors in Power Automate expressions (concat(), formatDateTime(), split(), etc.) can lead to failure.
6. Rate Limits Exceeded – If a service enforces rate limits and the flow exceeds them, it may fail unexpectedly.
7. API or Connector Limitations – Some connectors have execution time limits or quota restrictions.
8. Looping or Iteration Issues – A misconfigured loop (Apply to Each, Do Until) may cause an error.
9. Access Permission Issues – The flow may not have sufficient permissions to access a resource (e.g., SharePoint list, SQL database).
10. Unstable Third-Party APIs – If the flow calls an external API, a slow or unresponsive API can cause an unexpected failure.

---

3. Step-by-Step Troubleshooting Guide

Step 1: Check Flow Run History and Error Details

1. Open Power Automate (https://flow.microsoft.com).
2. Navigate to My Flows and select the failed flow.
3. Click Run History and open the failed execution.
4. Look for error messages or codes in the failed action.
5. Expand the error message details to find clues about what caused the failure.

---

Step 2: Check Microsoft Service Health for Outages

• Visit Microsoft 365 Service Health (https://status.office.com).
• If Microsoft services (e.g., SharePoint, Outlook, Dataverse) are down, wait for the issue to be resolved.
• If using a third-party API, check its status page for any downtime.

---

Step 3: Verify Flow Connections and Authentication

• Go to Power Automate > Data > Connections.
• Look for any expired or broken connections.
• Click Fix Connection or Reconnect to restore access.
• If using an API key or OAuth token, verify that it is still valid.

---

Step 4: Validate Expressions and Parameters

• If an expression is used in the failed action, check its syntax.
• Use the Expression Editor to test expressions before saving them.

❌ Incorrect Example:

concat('Hello',, 'World')  // Double commas cause an error

✔ Correct Example:

concat('Hello', ' ', 'World')

• Ensure parameters match the expected data types.
• If an action expects a number, but receives text, use int() to convert: plaintextCopyEditint('123')

---

Step 5: Reduce API Calls and Avoid Rate Limits

• Some connectors (e.g., SharePoint, Outlook, SQL) impose rate limits.
• If your flow makes multiple API calls:
  • Introduce a Delay action between requests.
  • Use batch processing instead of individual API calls.
  • Enable Pagination in actions like Get Items or List Rows.

---

Step 6: Review Looping and Iterations

• If using Apply to Each, ensure it does not process too many records.
• If using Do Until, set a maximum loop count to prevent infinite loops.
• If the flow references an empty array, add a condition to check for null values: plaintextCopyEditlength(variables('myArray')) > 0

---

Step 7: Check Access Permissions

• If the flow accesses SharePoint, SQL, Dataverse, or OneDrive, verify that:
  • The flow owner has access to the resource.
  • The service account permissions are correct.
  • The API permissions (if applicable) include the required scopes.

---

Step 8: Test the Flow with Sample Data

1. Modify the flow to use test inputs.
2. Manually trigger the flow and observe its behavior.
3. If dynamic content is missing, use coalesce() to provide a default value: coalesce(triggerBody()?['name'], 'Default Name')

---

Step 9: Duplicate and Rebuild the Flow

• If the error persists, try duplicating the flow and testing a fresh version.
• If necessary, rebuild the flow step by step to isolate the issue.

---

Step 10: Enable Detailed Logging (For Advanced Debugging)

• Add Scope actions to group related steps and catch errors.
• Use the Terminate Action with custom error messages to pinpoint failures.
• Enable Power Automate Analytics under Monitor > Process Insights.

---

4. Preventative Measures

To avoid unexpected errors in the future:

✔ Monitor Flow Run History – Regularly check for failures.
✔ Use Default Values – Prevent null errors using coalesce().
✔ Optimize API Calls – Reduce unnecessary requests and enable pagination.
✔ Implement Error Handling – Use Scope actions and retry policies.
✔ Test Before Deployment – Run test scenarios with different inputs.
✔ Ensure Proper Permissions – Verify user and API permissions.