A Step-by-Step Debugging Guide for Developers 

When Your App Randomly Goes Down. Few things cause more panic than this scenario: 

• Your app works locally 
• Deployment succeeds 
• Suddenly the app goes down 
• Logs show repeated restarts 
• No clear error message 

You Google one thing: “Azure App Service keeps restarting” 

This blog explains why Azure App Service restarts happen, how to identify the exact root cause, and how to fix it permanently—not just restart the service and hope. 

What Does “Azure App Service Keeps Restarting” Mean? 

When an Azure App Service keeps restarting, it means the application process is repeatedly crashing or failing health checks, causing the platform to automatically stop and restart the app to recover. This behavior usually indicates: 

• Application-level crashes 
• Resource exhaustion 
• Startup failures 
• Configuration errors 

Azure is not the problem—the app is. 

How Azure App Service Restart Cycles Work 

Azure App Service automatically restarts your app when: 

• The process crashes 
• Memory limits are exceeded 
• Startup takes too long 
• Health checks fail 
• Configuration changes occur 

This creates a restart loop, often called a crash loop. Understanding why Azure App Service keeps restarting your app is the key to fixing it. 

Most Common Reasons Azure App Service Keeps Restarting 

1. Application Startup Failure (Most Common Cause)

If your app fails during startup, Azure will keep restarting it. 

Typical causes: 

• Missing environment variables 
• Incorrect connection strings 
• Unhandled exceptions in Startup.cs 
• Invalid app settings 
• Dependency failures 

How to detect it 

• Check Application Logs 
• Look for startup exceptions 
• Review deployment logs 

Fix startup errors first—nothing else matters until the app boots successfully. 

2. Out of Memory (OOM) Issues

Azure App Service has strict memory limits based on the plan. 

Symptoms: 

• App restarts under load 
• No clear error in UI 
• Sudden crashes during traffic spikes 

Common reasons: 

• Memory leaks 
• Large object allocations 
• Infinite loops 
• Heavy caching in memory 

How to confirm 

• Check Metrics → Memory Working Set 
• Enable Application Insights 
• Look for memory spikes before restarts 

Fix 

• Optimize memory usage 
• Increase App Service Plan tier 
• Move caching to Redis or external stores 

3. App Service Plan Resource Limits

If CPU or memory hits the plan limit: 

• Azure throttles the app 
• Then restarts it for stability 

This is common on: 

• Free / Shared plans 
• Under-provisioned Basic plans 

Fix 

• Scale up the plan 
• Monitor CPU and memory continuously 
• Avoid running background jobs inside the app 

4. Failing Health Checks

If health checks are enabled and your app doesn’t respond in time, Azure restarts it. 

Causes: 

• Slow startup 
• Blocking database calls 
• Deadlocked threads 
• Long-running initialization code 

Fix 

• Keep health check endpoints lightweight 
• Avoid database calls in health checks 
• Increase health check timeout if needed 

5. Deployment and Configuration Issues

Apps can restart continuously after deployment due to: 

• Wrong runtime stack 
• Incorrect startup command 
• Mismatched framework version 
• Missing files 

Where to check 

• Configuration → General Settings 
• Startup command 
• Runtime version 

Always align your deployment config with how the app runs locally. 

6. Application Crashes at Runtime

Unhandled exceptions during execution will crash the app. 

Examples: 

• Null reference exceptions 
• Unhandled promise rejections (Node.js) 
• Thread crashes 
• Infinite recursion 

How to detect 

• Application Insights → Failures 
• Log stream 
• Crash stack traces 

Fix 

• Add global exception handling 
• Improve logging 
• Fix code-level bugs 

How to Diagnose Azure App Service Restart Issues (Step-by-Step) 

Step 1: Check Log Stream Immediately 

• Go to Monitoring → Log Stream 
• Watch real-time logs during restart 
• Look for fatal errors 

Step 2: Enable Application Insights 

• View Exceptions 
• Check Availability 
• Correlate crashes with traffic or deployment 

Step 3: Use Kudu Console 

• Access Advanced Tools → Kudu 
• Check file system 
• Review startup logs 
• Validate deployment artifacts 

Step 4: Monitor Metrics 

Key metrics to watch: 

• CPU Percentage 
• Memory Working Set 
• HTTP 5xx errors 
• Restart Count 

Patterns here usually reveal the cause. 

How to Stop Azure App Service Restart Loops Permanently 

• Fix startup logic before scaling 
• Move heavy jobs out of the web app 
• Optimize memory usage 
• Use proper logging 
• Scale plans based on real usage 
• Test with production-like data 

Restarting the app manually is not a fix—it’s a delay. 

When Azure App Service Is Not the Right Choice 

If your app: 

• Runs long background jobs 
• Needs heavy processing 
• Requires persistent connections 
• Has unpredictable memory usage 

Then consider: 

• Azure Functions 
• Containers 
• Kubernetes 
• Background worker services 

Choosing the wrong hosting model causes endless restarts. 

Final Thoughts: Restarts Are a Signal, Not a Failure 

When Azure App Service keeps restarting, Azure is protecting your system—not breaking it. 

Treat restarts as: 

• Architecture feedback 
• Resource signals 
• Stability warnings 

Fix the root cause once—and the problem disappears permanently. 

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