App Service Plan create throttled (429 / Error 51025) — stuck creating, never completes

Question

I'm trying to create an Azure App Service Plan (Linux, EP1 Elastic Premium tier) 

  via Terraform using the azapi provider, and the create operation never completes.

  

  Configuration:

  - SKU: EP1 (Elastic Premium)

  - OS: Linux (reserved = true)

  - Zone balancing: disabled

  - Region: UAE North

  - Resource type: Microsoft.Web/serverfarms

  

  What's happening:

  The Terraform apply sends a PUT to Microsoft.Web/serverfarms and sits in a 

  "creating" state indefinitely — I've let it run 30+ minutes with no error 

  returned to the client and no resource ever appearing (confirmed via 

  az appservice plan show, which returns ResourceNotFound the entire time).

  

  Checking the Activity Log for the resource group shows repeated failures on 

  the same operation:

  

  Operation: Microsoft.Web/serverfarms/write ("Update hosting plan")

  Status: Failed

  Error Code: 429

  ExtendedCode: 51025

  Message: "App Service Plan Create operation is throttled for subscription 

  e8eedcd1-9177-4ce7-abb0-14ef427fda1f . Please contact support if issue persists."

  

  This has now happened across three separate attempts on the same day, each 

  left running 5-30 minutes before either failing outright or hanging with no 

  resolution. I recently had my subscription's AZ VM quota increased in this 

  region right before these attempts, in case that's related.

  

  Questions:

  1. Is this a subscription-level rate limit specifically on App Service Plan 

     creation, separate from vCPU/AZ quota?

  2. Is there a typical cooldown period before retrying, or does this require 

     a manual reset on Microsoft's side?

  3. Could the recent quota increase have triggered a temporary re-evaluation 

     or lock on this subscription's App Service capacity?

  

  Any guidance on resolving this or confirming whether this needs an internal 

  Azure-side fix would be appreciated.

  

  Tag 

  azure-app-service

  

  azure-web-app-service

Answer 1

Hello Jeevanantham N,

Greetings! Thanks for raising this question in the Q&A forum.

The root cause here is a known Azure App Service throttling mechanism, not a quota or capacity problem. Extended error code 51025 specifically means the App Service resource provider has rate-limited App Service Plan create operations for your subscription in that region, independent of your vCPU/AZ compute quota. This throttle is typically triggered when there are several create or failed-create attempts on App Service Plans within a short window, and once it engages it commonly blocks further plan creation for up to 48 hours in that specific region.

Your three attempts in one day, each left hanging or failing, are very likely what tripped the counter rather than anything related to the AZ VM quota increase. The quota bump and the throttle are handled by different subsystems, so it is unlikely the two are directly connected, though it is reasonable that reviewing a subscription's capacity around the same time could coincide with increased backend scrutiny.

To answer your three questions directly:

1. Yes, this is a subscription and region specific rate limit on App Service Plan create operations, separate from vCPU/AZ quota. Your VM quota increase did not cause it directly.
2. The cooldown is generally 48 hours per region. There is no self-service reset; Microsoft support can sometimes clear it manually if you open a ticket.
3. The quota increase itself is unlikely to be the trigger. Repeated create attempts against the same region within a short timeframe are the far more common cause.

Here is how to move forward:

1. Stop retrying in UAE North for now. Each additional failed or hung create attempt can extend the throttle window rather than clear it.
2. Confirm the resource never landed by checking the Activity Log entries for Microsoft.Web/serverfarms/write in the affected resource group, and cross-check with az appservice plan list --resource-group <rg> to rule out a partially created orphaned plan.
3. Test in a different region (or a different subscription if you have one available) to confirm the throttle is scoped to UAE North specifically and not tenant-wide.
4. Avoid parallel or rapid re-applies from Terraform. If your pipeline retries automatically on failure, add a delay or disable auto-retry for this resource until the throttle clears, since Terraform re-applying quickly is a common trigger for this exact error.
5. Open an Azure Support ticket referencing subscription ID e8eedcd1-9177-4ce7-abb0-14ef427fda1f, the region (UAE North), the resource group, extended error code 51025, and the UTC timestamps of your three attempts. Support can confirm whether the throttle is active and, in many cases, clear it manually rather than making you wait the full 48 hours. A Basic support plan is sufficient to open a billing/technical ticket for this kind of platform-side throttle.
6. Once cleared, if you are creating multiple plans going forward, stagger the creates with a short delay between each rather than issuing them back to back, since bursts of create operations are what commonly re-trigger this throttle.

If this answer helps you kindly accept the answer which will help others who have similar questions.

Best Regards,

Jerald Felix.