# Error Codes for SDKs

The SDK will return one of the following errors (Password (SDKv1), API Key (SDKv2), mTLS, OIDC respectively) typically when creating the SDK client:

```undefined
SDKv1:
tsm authentication failed
oidc access token unauthorized

SDKv2:
unable to fetch protocol information: tsm authentication failed: unauthorized API key
unable to fetch protocol information: tsm authentication failed: unauthorized certificate
unable to fetch protocol information: tsm authentication failed: unauthorized OIDC access token
```

The server error log will contain one of the following entries:

```undefined
level=info msg="token validation failed: invalid token"
level=info msg="invalid API key"
level=info msg="certificate is not valid"
level=info msg="unable to validate access token: <cause>"
```

If the authentication mechanism is not enabled on the server the following messages will be in the server log:

```undefined
level=info msg="Received bearer token but token authentication is not enabled"
level=info msg="Received API key but API key authentication is not enabled"
level=info msg="Received client certificate but TLS authentication is not enabled"
level=info msg="Received token but oidc access token authentication is not enabled"
```

Other errors may describe parse errors or lack of support for some of the tokens.

## Note on SDKv1 401 Errors

In SDKv1 the username and password authentication occur through time-limited tickets that expire. Upon expiry, a `401` error is logged, after which the SDK automatically requests a new ticket and retries the command. Therefore, when using SDKv1, it is necessary to determine whether the 401 error is a result of a specific command or simply due to ticket reissuing; in all other situations, a `401` error signifies that the authentication was not accepted.