ExtendSync for Outlook may temporarily fail to read or write data to NetSuite when your account has reached its maximum concurrency limit.

When this occurs, ExtendSync retries automatically and notifies the user with messages like:

“Your NetSuite account is currently busy serving other requests. ExtendSync will attempt the operation a few more times.”

If all retries fail, you may see:

“Your NetSuite account was busy serving other requests and prevented us from fetching matching results. Please retry.”

What This Means for Users

NetSuite is temporarily too busy to accept additional requests
ExtendSync is unable to fetch or save data during that window
This is a temporary condition, not a configuration or permission error

What End Users Should Do

When you see a concurrency message:

Wait a few moments.
Click Retry or repeat the action.

In most cases, the operation succeeds once concurrency frees up.

💡 If the error appears frequently, share this article with your NetSuite Administrator.

Why This Happens (NetSuite Concurrency Limits)

NetSuite enforces strict concurrency limits on Web Services requests.

Every integration (ExtendSync, RESTlets, scheduled scripts, third-party apps) consumes concurrency
When all queues are in use, additional requests are rejected
ExtendSync includes retry logic, but cannot bypass NetSuite’s limits

This is expected NetSuite behavior.

For NetSuite Administrators

NetSuite has a strict concurrency policy and depending on your account concurrency your users may see this error from time to time and will have to retry the operation.

ExtendSync Outlook tries to work around these concurrency limitations with retry logic and attempts to fetch matching NetSuite records. However, there are cases where other integration applications are completely using your queues and in such a case ExtendSync alerts your users and asks them to retry.

How to Diagnose Concurrency Errors

1. Check the Global Search Script Log

If users experience timeouts or failure to retrieve matching records, you can confirm concurrency issues in the Execution Log:

In NetSuite, go to:
Customization → Scripting → Script Deployment
Search for:
customdeploy_celigo_global_search
Click Execution Log
Look for this error:
SSS_REQUEST_LIMIT_EXCEEDED

This indicates that ExtendSync’s requests exceeded your account’s concurrency limits

2. Review Your Account Concurrency Limits

Navigate to:
Setup → Integration → Web Services Preferences
Locate Account Concurrency Limit.

This value represents the maximum number of concurrent Web Services requests your account can handle.

➡️ Refer to NetSuite’s concurrency cheat sheet to understand limits and scaling

3. Monitor Integration Usage & Identify Traffic Spikes

NetSuite recommends installing the Application Performance Management (APM) SuiteApp to monitor:

Web Services usage
RESTlet concurrency
Integration load patterns
High-traffic periods

APM provides visibility into which integrations (including non-ExtendSync apps) are consuming your concurrency.

➡️ Learn more about APM SuiteApp

Best Practices to Prevent Concurrency Errors

Review your integration schedule to avoid running heavy API jobs during peak hours.
Use APM or logs to determine which integrations are consuming concurrency.
Set up load balancing or staggering of scheduled scripts.
Ensure roles used by ExtendSync have proper permissions to avoid unnecessary retries.
Work with your admin team to regularly monitor Web Services health.