Troubleshooting Microsoft Action Flow modules
We've gathered some resources and troubleshooting tips that will help you resolve some problems you might encounter when working with Action Flow modules for Microsoft apps.
Symptoms
Your Action Flow operation fails with the following error: 429 Application is Over its Mailbox Concurrency Limit.
Cause
The 429 error indicating a "MailboxConcurrency limit" in Microsoft services occurs when the number of requests to an Outlook resource (like a mailbox or calendar) exceeds the set concurrency limits. Only four concurrent requests are allowed to a single mailbox or resource. If your application tries to send more than four simultaneous requests, you may encounter throttling, resulting in the 429 error.
You can find Microsoft API limits in Outlook service limits.
Solution
You can use different methods to deal with this limitation:
Add the Sleep module before the module that is causing the error. Set the delay to fit into the number of requests in the time limit. For example, if the app is limited to 10 requests per minute, set the delay to 6 seconds.
Check our documentation on Error Handling in Action Flows, where you can set a directive, in case of an error or warning during execution.
Consider adding a Break Module which will trigger automatic retry of your execution in case of an error.
Symptoms
The service temporarily unavailable is usually signaled with a [503] error code.
Cause
There might be various causes for this issue. The most common ones are:
Service Downtime: the Microsoft Graph API might be experiencing an outage or undergoing maintenance.
Throttling: your application may have exceeded rate limits or concurrency limits. In such cases, the API may throttle requests temporarily, leading to a 503 error.
High traffic or resource limits: If your requests are resource-intensive or the service is under heavy load, it may return a 503 error until the load decreases.
Network issues: occasionally, network issues between your application and Microsoft Graph servers can cause temporary disruptions.
Retry the execution of your Action Flow. Consider adding a Break Module which will trigger automatic retry of your execution in case of an error.