How To Resolve the '500 - Robot Service Down' Error While Opening a UiPath App URL in Browser

[system]

How to resolve the '500 - Robot Service Down' Error When Opening a UiPath App URL in browser?

Issue Description

Users with UiPath Studio/Robot attempting to access the UiPath application URL encounter a 500 error with the following message:

Process Error

500 - Robot Service down

Browser Console Logs (Ctrl+Shift+I):

ID63579177c2474a09918ac2941237e973?el=VB:1 Access to XMLHttpRequest at 'http://localhost:2323/GetPort' from origin 'https://cloud.UiPath.com' has been blocked by CORS policy: Permission was denied for this request to access the loopback address space.

or

Process Error

500 - Robot Service down


Browser Console Logs (Ctrl+Shift+I):

Access to XMLHttpRequest at 1D3be35d6d960548c0b2..cfb91a91dfd?e1=VB:1 ' http://localhost:2323/GetPort' from origin ‘https://cloud.uipath.com' has been blocked by CORS policy: Permission was denied for this request to access the “unknown” address space.

Root Cause

• The error occurs because the Local Network Access permission is not enabled in the browser for the UiPath App URL. This permission is required for the app to communicate with local services (localhost) from the cloud-based origin.

Affected Users

• Users accessing the application using the internal UiPath App URL

• Users experiencing CORS policy blocks when the app attempts to connect to localhost services

Resolution

• In the address of the App URL, click on the View Site information -> Enable the Local network access permission.

• Restart the impacted browser Apps URL page

• Retry to run the attended process from the Apps URL

Alternative Resolution

If the above steps don't resolve the issue:

Clear Browser Cache and Cookies:

• Clear your browser's cache and cookies

• Close and reopen the browser

• Repeat the permission-enabling steps above