Azure Function App Flex Consumption migration fails with ServerFarmCreationNotAllowed

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Pontem 0 Reputation points

I am trying to migrate an existing Linux Consumption Azure Function App to Flex Consumption, but the migration fails after the app passes the eligibility check.

I need to migrate this Function App from Linux Consumption to Flex Consumption so that I can use a newer Python version (3.13).

Debugged and confirmed this potential reasons:

Microsoft.Web or Microsoft.App wasn’t fully registered. (checked both are registered)
The subscription offer is still effectively restricted. (canada central is not restricted)
An Azure Policy blocks plan creation. (confirmed there's no policy that blocks the creation)

Command I ran

az functionapp flex-migration start \
 --source-name "<source-function-app>" \
 --source-resource-group "<source-resource-group>" \
 --name "<new-flex-function-app>" \
 --resource-group "<target-resource-group>"

Result

The app passes the eligibility check:

Validating that the app '<source-function-app>' is eligible for Flex Consumption migration...
Source app '<source-function-app>' is eligible for Flex Consumption migration.

Then creation of the new Flex Consumption Function App fails:

Creating Flex Consumption function app '<new-flex-function-app>' in resource group '<target-resource-group>'...
Using source app's storage account '<source-storage-account>' for function app '<new-flex-function-app>'
There was an error creating the Flex Consumption function app. Please address the issue and try again.
The subscription 'ee8ce930-...-484a95bddbfa' is not allowed to create or update the serverfarm.

Azure troubleshooting detector output

The Azure Portal detector shows multiple occurrences of:

Detected SubscriptionNotAllowedToCreateOrUpdateServerfarm

Example 1:

Resource: ServerFarm - <serverfarm-name-1>
Last Error Timestamp: 2026-06-08 16:41:33
Last Error CorrelationId: 507ed0d3-564e-4f04-a278-f896d319268d
Total Number of Occurrences: 4
Error Message: The subscription 'ee8ce930-...-484a95bddbfa' is not allowed to create or update the serverfarm.

Not sure whether this subscription is blocked from creating Flex Consumption serverfarms in Canada Central, or whether there is a backend subscription restriction/quota/policy preventing Microsoft.Web/serverfarms creation?

We would like to migrate this Function App to Flex Consumption so it can support the required newer Python version.

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Pravallika KV 17,025 Reputation points • Microsoft External Staff • Moderator

Hi @Pontem ,

Thanks for reaching out to Microsoft Q&A.

After further investigation, our backend team has implemented a fix to unblock the customer's subscription.

You can retry az functionapp flex-migration start to complete the Flex Consumption migration.
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Pontem 0 Reputation points

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Pontem 0 Reputation points

@Pravallika KV Thank you for your response, these are the answers:

I tried it but I cannot create a new flex consumption app (not in cli migration) - yes both in the same region and subscription.
The role is Owner
No, unfortunately the project should only be in the same resource group and subscription.
below are the full --debug error output
Linux Consumption app’s current runtime stack is Python v3.11

cli.azure.cli.command_modules.appservice.custom: There was an error creating the Flex Consumption function app. Please address the issue and try again.
cli.azure.cli.core.azclierror: Traceback (most recent call last):
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 789, in _run_job
 result = cmd_copy(params)
 ^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 335, in __call__
 return self.handler(*args, **kwargs)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/core/commands/command_operation.py", line 120, in handler
 return op(**command_args)
 ^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/command_modules/appservice/custom.py", line 1278, in migrate_consumption_to_flex
 create_functionapp(cmd, resource_group, name, storage_account, flexconsumption_location=source.location,
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/command_modules/appservice/custom.py", line 8507, in create_functionapp
 raise ex
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/command_modules/appservice/custom.py", line 8405, in create_functionapp
 plan_info = create_flex_app_service_plan(
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/command_modules/appservice/custom.py", line 7788, in create_flex_app_service_plan
 poller = client.app_service_plans.begin_create_or_update(resource_group_name, name, plan_def)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/core/tracing/decorator.py", line 119, in wrapper_use_tracer
 return func(*args, **kwargs)
 ^^^^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/mgmt/web/v2024_11_01/operations/_app_service_plans_operations.py", line 1502, in begin_create_or_update
 raw_result = self._create_or_update_initial(
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/mgmt/web/v2024_11_01/operations/_app_service_plans_operations.py", line 1401, in _create_or_update_initial
 raise HttpResponseError(response=response, model=error, error_format=ARMErrorFormat)
azure.core.exceptions.HttpResponseError: Operation returned an invalid status 'Forbidden'
Content: {"Code":"Forbidden","Message":"The subscription 'ee8ce930-9386-4f0d-832f-484a95bddbfa' is not allowed to create or update the serverfarm.","Target":null,"Details":[{"Message":"The subscription 'ee8ce930-9386-4f0d-832f-484a95bddbfa' is not allowed to create or update the serverfarm."},{"Code":"Forbidden"},{"ErrorEntity":{"ExtendedCode":"70001","MessageTemplate":"The subscription '{0}' is not allowed to create or update the serverfarm.","Parameters":["ee8ce930-9386-4f0d-832f-484a95bddbfa"],"Code":"Forbidden","Message":"The subscription 'ee8ce930-9386-4f0d-832f-484a95bddbfa' is not allowed to create or update the serverfarm."}}],"Innererror":null}
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
 File "/usr/lib64/az/lib/python3.12/site-packages/knack/cli.py", line 233, in invoke
 cmd_result = self.invocation.execute(args)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 677, in execute
 raise ex
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 820, in _run_jobs_serially
 results.append(self._run_job(expanded_arg, cmd_copy))
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/core/commands/__init__.py", line 812, in _run_job
 return cmd_copy.exception_handler(ex)
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 File "/usr/lib64/az/lib/python3.12/site-packages/azure/cli/command_modules/appservice/commands.py", line 46, in _ex_handler
 raise ex
knack.util.CLIError: The subscription 'ee8ce930-9386-4f0d-832f-484a95bddbfa' is not allowed to create or update the serverfarm.
cli.azure.cli.core.azclierror: The subscription 'ee8ce930-9386-4f0d-832f-484a95bddbfa' is not allowed to create or update the serverfarm.
az_command_data_logger: The subscription 'ee8ce930-9386-4f0d-832f-484a95bddbfa' is not allowed to create or update the serverfarm.
cli.knack.cli: Event: Cli.PostExecute [<function AzCliLogging.deinit_cmd_metadata_logging at 0x7fea8a069440>]
az_command_data_logger: exit code: 1
cli.__main__: Command ran in 26.621 seconds (init: 0.067, invoke: 26.555)
telemetry.main: Begin splitting cli events and extra events, total events: 1
telemetry.main: Finish splitting cli events and extra events, cli events: 1
telemetry.save: Save telemetry record of length 4345 in cache file under /home/pontem/.azure/telemetry/20260608192343142
telemetry.main: Begin creating telemetry upload process.
telemetry.process: Creating upload process: "/usr/bin/python3.12 /usr/lib/az/lib/python3.12/site-packages/azure/cli/telemetry/__init__.py /home/pontem/.azure /home/pontem/.azure/telemetry/20260608192343142"
telemetry.process: Return from creating process 1154
telemetry.main: Finish creating telemetry upload process.

and these are the issue log in portal:

Detected SubscriptionNotAllowedToCreateOrUpdateServerfarm for ServerFarm - asp-pontem-644e

Detected SubscriptionNotAllowedToCreateOrUpdateServerfarm for DeploymentValidation - Microsoft.Web-FunctionApp-Portal-3abb8ed9-8d89

Description - The subscription xx is not allowed to create or update the serverfarm Recommended Action - If issue persists, please contact support with the timestamp and correlationId from Activity Logs or Deployment History Last Error TimeStamp - 2026-06-08 16:47:17 Last Error CorrelationId - 68172f92-1bf2-4a39-aafb-e90afb36e009 Total Number of Occurrences - 1 Error Message - The template deployment 'Microsoft.Web-FunctionApp-Portal-3abb8ed9-8d89' is not valid according to the validation procedure. The following resource provider(s) - 'Microsoft.Web/serverFarms (2024-11-01)' reported preflight validation errors. Tracking id is '05ecfec8-b006-4407-bdcb-2970a3d61cef'. See inner errors for details. Error code:ServerFarmCreationNotAllowed message:The subscription 'ee8ce930-...-484a95bddbfa' is not allowed to create or update the serverfarm.

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Pravallika KV 17,025 Reputation points • Microsoft External Staff • Moderator

Could you please share the details requested over private message? @Pontem
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Pravallika KV 17,025 Reputation points • Microsoft External Staff • Moderator

Hi @Pontem , could you check now and confirm if the issue is resolved?

URL: https://learn.microsoft.com/en-us/answers/questions/5914798/azure-function-app-flex-consumption-migration-fail