[Yandex Cloud documentation](../../index.md) > [Yandex Managed Service for Apache Airflow™](../index.md) > FAQ

# General questions about Managed Service for Apache Airflow™

### How do I fix the IP address range overlap error when creating a cluster? {#ip-addresses}

When creating a Managed Service for Apache Airflow™ cluster you may get the following error:

```text
user subnet overlaps with service network range 10.248.0.0/13, see documentation for details
```

This error means that when creating the cluster, you selected a subnet whose IP address range overlaps with the `10.248.0.0/13` address range of the service subnet. In this subnet, Yandex Cloud manages the Managed Service for Apache Airflow™ cluster components.

To fix this error, select another subnet whose IP address range does not overlap with the service subnet range. Learn more about cluster subnet requirements in [Network](../concepts/network.md#subnet-requirements).

### How can I fix the no permission error when attaching a service account to a cluster? {#attach-service-account}

#### How can I fix the no permission error when connecting a service account to the cluster? {#attach-service-account}

Error message:

```text
ERROR: rpc error: code = PermissionDenied desc = you do not have permission to access the requested service account or service account does not exist
```

This error occurs if you link a service account to a cluster while creating or modifying it.

**Solution**
[Assign](../../iam/operations/roles/grant.md) the [iam.serviceAccounts.user](../../iam/security/index.md#iam-serviceAccounts-user) role or higher to your Yandex Cloud account.

### How do I fix the `No module named 'airflow.providers.postgres.operators'` error? {#airflow-provider-postgres-operators}

When accessing a Managed Service for PostgreSQL cluster from an Managed Service for Apache Airflow™ cluster, you may get this error:

```bash
Broken DAG: [/opt/airflow/dags/postgre.py] Traceback (most recent call last):
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/opt/airflow/dags/postgre.py", line 2, in <module>
    from airflow.providers.postgres.operators.postgres import PostgresOperator
ModuleNotFoundError: No module named 'airflow.providers.postgres.operators'
```

`apache-airflow-providers-postgres` 5.13.1 is used by default. The error may occur if using `PostgresOperator` with newer provider versions.

**Solution**:

If using a newer provider version, use SQLExecuteQueryOperator instead of PostgresOperator. For more information, see [the official documentation](https://airflow.apache.org/docs/apache-airflow-providers-postgres/6.0.0/operators/postgres_operator_howto_guide.html).

### How do I fix the `AirflowException: Unknown hook type "postgres"` error? {#airflow-provider-postgres-operators-2}

When accessing a Managed Service for PostgreSQL cluster from an Managed Service for Apache Airflow™ cluster, you may get this error:

```bash
Task failed with exception: source="task"
AirflowException: Unknown hook type "postgres"
```

By default, the `apache-airflow-providers-postgres` provider is not installed in Managed Service for Apache Airflow™ clusters with Apache Airflow™ versions above 3.0.

**Solution**:

When creating or updating a Managed Service for Apache Airflow™ cluster, add the `apache-airflow-providers-postgres` pip package under **Dependencies**.

### How do I fix the `No module named 'airflow_clickhouse_plugin'` error? {#airflow-clickhouse-plugin}

When accessing a Managed Service for ClickHouse® cluster from an Managed Service for Apache Airflow™ cluster, you may get this error:

```bash
Traceback (most recent call last):
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/opt/airflow/dags/dags/clickhouse.py", line 2, in <module>
    from airflow_clickhouse_plugin.hooks.clickhouse import ClickHouseHook
ModuleNotFoundError: No module named 'airflow_clickhouse_plugin'
```

By default, the `airflow-clickhouse-plugin` plugin is not installed in Managed Service for Apache Airflow™.

**Solution**:

When creating or updating a Managed Service for Apache Airflow™ cluster, add the `airflow-clickhouse-plugin` pip package under **Dependencies**.

### How do I fix the `SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED]` error? {#airflow-clickhouse-ssl}

When trying to connect to a Managed Service for ClickHouse® cluster from a Managed Service for Apache Airflow™ cluster, you may get this error:

```bash
SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: self signed certificate in certificate chain (_ssl.c:1123)
```

**Solution:**

1. Download the SSL certificate at [https://storage.yandexcloud.net/cloud-certs/CA.pem](https://storage.yandexcloud.net/cloud-certs/CA.pem).
1. Place the certificate in the root of the DAG file bucket.
1. In the connection settings, specify the certificate path in the `ca_certs` field.

   [Value of the secret you created](../operations/clickhouse.md#create-lockbox-secret):
   
   ```json
   {
     "conn_type": "clickhouse",
     "host": "<ClickHouse®_cluster_host_FQDN>",
     "port": 9440,
     "schema": "default-bd",
     "login": "admin",
     "password": "admin-password",
     "extra": {
         "secure": "True",
         "ca_certs": "/opt/airflow/dags/CA.pem"
     }
   }
```