You create a custom analytics rule to detect threats in Azure Sentinel.

In Microsoft Sentinel, a custom analytics (scheduled) rule can fail intermittently for transient reasons. According to Microsoft’s guidance on troubleshooting analytics rules:

A transient failure is one that occurs due to a temporary condition and does not require human intervention to resolve. Examples include: • The rule query takes too long to run and times out. • Connectivity issues between the data sources and Log Analytics, or between Log Analytics and Microsoft Sentinel.Microsoft Sentinel will attempt to run the rule again after a delay, up to predetermined retries.

Therefore, option A (rule query taking too long) and option D (connectivity issues) are correct causes of intermittent failures.

On the other hand, permanent failures or configuration-level issues can lead to rules being “auto-disabled,” but those are not intermittent failures. The documentation lists permanent failure causes like the target workspace being deleted or permissions to data sources being changed. Microsoft Learn

For example:

Option B (the target workspace was deleted) is a permanent cause, not an intermittent one. Once the workspace is gone, the rule can never run.

Option C (permissions to the data sources of the rule query were modified) is also a permanent failure scenario, because once permissions change, the rule loses access until corrected, which is not something that happens intermittently unless someone is repeatedly toggling permissions.