diff --git a/packages/sdk-rtl/src/authSession.ts b/packages/sdk-rtl/src/authSession.ts
index 0eeae4e2d..8aefe8677 100644
--- a/packages/sdk-rtl/src/authSession.ts
+++ b/packages/sdk-rtl/src/authSession.ts
@@ -27,7 +27,6 @@
 import type { IRequestProps, ITransport, SDKResponse } from './transport'
 import { sdkError } from './transport'
 import type { IApiSettings } from './apiSettings'
-import type { Url } from './constants'
 
 /**
  * Same as the Looker API access token object
@@ -60,11 +59,11 @@ export interface IError {
   /**
    * Error details (read-only)
    */
-  message: string
+  message: string | null
   /**
    * Documentation link (read-only)
    */
-  documentation_url: Url
+  documentation_url: string | null
 }
 
 /**