diff --git a/client/src/www/app/app.ts b/client/src/www/app/app.ts
index e067987e8a..ae84354d1e 100644
--- a/client/src/www/app/app.ts
+++ b/client/src/www/app/app.ts
@@ -204,22 +204,30 @@ export class App {
       toastMessage = this.localize('error-connection-configuration');
       buttonMessage = this.localize('error-details');
       buttonHandler = () => {
-        this.showErrorDetailDialog(error);
+        this.showErrorCauseDialog(error);
       };
     } else if (error instanceof errors.SessionConfigFetchFailed) {
       toastMessage = this.localize('error-connection-configuration-fetch');
       buttonMessage = this.localize('error-details');
       buttonHandler = () => {
-        this.showErrorDetailDialog(error);
+        this.showErrorCauseDialog(error);
       };
     } else if (error instanceof errors.ProxyConnectionFailure) {
       toastMessage = this.localize('error-connection-proxy');
       buttonMessage = this.localize('error-details');
       buttonHandler = () => {
-        this.showErrorDetailDialog(error);
+        this.showErrorCauseDialog(error);
       };
     } else if (error instanceof errors.SessionConfigError) {
       toastMessage = error.message;
+    } else if (error instanceof errors.SessionProviderError) {
+      toastMessage = error.message;
+      buttonMessage = this.localize('error-details');
+
+      console.log(error, error.message, error.details);
+      buttonHandler = () => {
+        this.showErrorDetailsDialog(error.details);
+      };
     } else {
       const hasErrorDetails = Boolean(error.message || error.cause);
       toastMessage = this.localize('error-unexpected');
@@ -227,7 +235,7 @@ export class App {
       if (hasErrorDetails) {
         buttonMessage = this.localize('error-details');
         buttonHandler = () => {
-          this.showErrorDetailDialog(error);
+          this.showErrorCauseDialog(error);
         };
       }
     }
@@ -573,7 +581,7 @@ export class App {
     return new Promise<boolean>(resolve => resolve(confirm(message)));
   }
 
-  private showErrorDetailDialog(error: Error) {
+  private showErrorCauseDialog(error: Error) {
     let message = error.toString();
 
     if (error.cause) {
@@ -581,10 +589,15 @@ export class App {
       message += error.cause.toString();
     }
 
-    // Temporarily use window.alert here
     return alert(message);
   }
 
+  private showErrorDetailsDialog(details: string) {
+    if (!details) return;
+    
+    return alert(details);
+  }
+
   //#endregion UI dialogs
 
   // Helpers:
diff --git a/client/src/www/app/outline_server_repository/access_key_serialization.ts b/client/src/www/app/outline_server_repository/access_key_serialization.ts
index 12e3d061b7..035ed437b0 100644
--- a/client/src/www/app/outline_server_repository/access_key_serialization.ts
+++ b/client/src/www/app/outline_server_repository/access_key_serialization.ts
@@ -39,7 +39,7 @@ function parseShadowsocksSessionConfigJson(responseBody: string): ShadowsocksSes
   const responseJson = JSON.parse(responseBody);
 
   if ('error' in responseJson) {
-    throw new errors.SessionConfigError(responseJson.error.message);
+    throw new errors.SessionProviderError(responseJson.error.message, responseJson.error.details);
   }
 
   const {method, password, server, server_port, prefix} = responseJson;
@@ -85,7 +85,7 @@ export async function fetchShadowsocksSessionConfig(configLocation: URL): Promis
 
     return parseShadowsocksSessionConfigJson(responseBody);
   } catch (cause) {
-    if (cause instanceof errors.SessionConfigError) {
+    if (cause instanceof errors.SessionProviderError) {
       throw cause;
     }
 
diff --git a/client/src/www/model/errors.ts b/client/src/www/model/errors.ts
index 8a6a743158..8167bbe29f 100644
--- a/client/src/www/model/errors.ts
+++ b/client/src/www/model/errors.ts
@@ -47,8 +47,18 @@ export class SessionConfigFetchFailed extends CustomError {
 }
 
 export class SessionConfigError extends CustomError {
-  constructor(message: string) {
+  constructor(message: string, options?: {cause?: Error}) {
+    super(message, options);
+  }
+}
+
+export class SessionProviderError extends CustomError {
+  readonly details: string | undefined;
+
+  constructor(message: string, details?: string) {
     super(message);
+
+    this.details = details;
   }
 }