> ## Documentation Index
> Fetch the complete documentation index at: https://ai.easyaf.dev/llms.txt
> Use this file to discover all available pages before exploring further.

# OAuthTokenException

> The single exception type an outbound token, device authorization, or polling request throws when the authorization server answers with an RFC 6749 section 5...

## Definition

**Assembly:** Microsoft.OData.Mcp.Authentication.dll

**Namespace:** Microsoft.OData.Mcp.Authentication.Outbound

**Inheritance:** System.Exception

## Syntax

```csharp theme={null}
Microsoft.OData.Mcp.Authentication.Outbound.OAuthTokenException
```

## Summary

The single exception type an outbound token, device authorization, or polling request throws when the
authorization server answers with an RFC 6749 section 5.2 error payload, or when the request never
reached one.

## Remarks

Per `AUTH-12` no member of this type ever carries an access token, refresh token, device code, or
client secret: [OAuthTokenException.Error](https://ai.easyaf.dev/odata-mcp/api-reference/Microsoft/OData/Mcp/Authentication/Outbound/OAuthTokenException.md#error) and [OAuthTokenException.ErrorDescription](https://ai.easyaf.dev/odata-mcp/api-reference/Microsoft/OData/Mcp/Authentication/Outbound/OAuthTokenException.md#errordescription) are copied straight from the
server's error payload, and the composed [Message](https://learn.microsoft.com/dotnet/api/system.exception.message) repeats only those two values
and the HTTP status. RFC 8628 device code polling reuses this type for its `authorization_pending`,
`slow_down`, `expired_token`, and `access_denied` answers, which is why
[OAuthTokenException.Error](https://ai.easyaf.dev/odata-mcp/api-reference/Microsoft/OData/Mcp/Authentication/Outbound/OAuthTokenException.md#error) is exposed as a value a caller can branch on rather than only formatted into the
message.

## Examples

```csharp theme={null}
try
{
    var response = await tokenEndpointClient.PostAsync(tokenEndpoint, form, clientId, clientSecret, authMethod, cancellationToken);
}
catch (OAuthTokenException ex) when (ex.Error == ODataMcpAuthConstants.ErrorAuthorizationPending)
{
    // Keep polling.
}
```

## Constructors

###  .ctor

Initializes a new instance of the [OAuthTokenException](https://ai.easyaf.dev/odata-mcp/api-reference/Microsoft/OData/Mcp/Authentication/Outbound/OAuthTokenException.md) class for an error payload the
authorization server returned.

#### Syntax

```csharp theme={null}
public OAuthTokenException(string error, string errorDescription, int statusCode)
```

#### Parameters

| Name | Type | Description |
| - | - | - |
| `error` | `string` | The RFC 6749 error code, such as `invalid_grant`. |
| `errorDescription` | `string?` | The human readable description, or [`null`](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when the server supplied none. |
| `statusCode` | `int` | The HTTP status code the request failed with, or `0` when there was no response. |

#### Exceptions

| Exception | Description |
| - | - |
| `ArgumentException` | Thrown when *error* is [`null`](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null), empty, or whitespace. |

###  .ctor

Initializes a new instance of the [OAuthTokenException](https://ai.easyaf.dev/odata-mcp/api-reference/Microsoft/OData/Mcp/Authentication/Outbound/OAuthTokenException.md) class for an error payload the
authorization server returned, or a transport failure, that another exception caused.

#### Syntax

```csharp theme={null}
public OAuthTokenException(string error, string errorDescription, int statusCode, System.Exception inner)
```

#### Parameters

| Name | Type | Description |
| - | - | - |
| `error` | `string` | The RFC 6749 error code, or `transport_error` for a request that never reached a server. |
| `errorDescription` | `string?` | The human readable description, or [`null`](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when there is none. |
| `statusCode` | `int` | The HTTP status code the request failed with, or `0` when there was no response. |
| `inner` | `System.Exception` | The exception that caused this failure. |

#### Exceptions

| Exception | Description |
| - | - |
| `ArgumentException` | Thrown when *error* is [`null`](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null), empty, or whitespace. |

###  .ctor

Initializes a new instance of the [OAuthTokenException](https://ai.easyaf.dev/odata-mcp/api-reference/Microsoft/OData/Mcp/Authentication/Outbound/OAuthTokenException.md) class with a message and the
exception that caused this failure.

#### Syntax

```csharp theme={null}
public OAuthTokenException(string message, System.Exception inner)
```

#### Parameters

| Name | Type | Description |
| - | - | - |
| `message` | `string` | The error message. Must never carry a token, device code, or client secret. |
| `inner` | `System.Exception` | The exception that caused this failure. |

#### Remarks

[OAuthTokenException.Error](https://ai.easyaf.dev/odata-mcp/api-reference/Microsoft/OData/Mcp/Authentication/Outbound/OAuthTokenException.md#error) reads as [Empty](https://learn.microsoft.com/dotnet/api/system.string.empty) and [OAuthTokenException.StatusCode](https://ai.easyaf.dev/odata-mcp/api-reference/Microsoft/OData/Mcp/Authentication/Outbound/OAuthTokenException.md#statuscode) as `0` for
an instance built this way, because neither an error code nor a response status is known.

## Properties

###  Error

Gets the RFC 6749 error code the authorization server returned, such as `invalid_grant`, or
`transport_error` when the request never reached a server.

#### Syntax

```csharp theme={null}
public string Error { get; }
```

#### Property Value

Type: `string`
[Empty](https://learn.microsoft.com/dotnet/api/system.string.empty) when this instance was constructed with only a message and an inner
exception.

###  ErrorDescription

Gets the human readable `error_description` the authorization server returned, or
[`null`](https://learn.microsoft.com/dotnet/csharp/language-reference/keywords/null) when it supplied none.

#### Syntax

```csharp theme={null}
public string ErrorDescription { get; }
```

#### Property Value

Type: `string?`

###  StatusCode

Gets the HTTP status code the failing request returned.

#### Syntax

```csharp theme={null}
public int StatusCode { get; }
```

#### Property Value

Type: `int`
`0` when the request never produced a response, such as a transport failure.


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