Candidates attempting to access the RRB TCS iON portal are encountering temporary server access issues.
The portal displays 'Unable to service request' along with HTTP 400 and 403 forbidden status codes.
Heavy web traffic from thousands of applicants or backend system maintenance often causes temporary outages.
Try clearing browser cache, opening incognito mode, or re-trying after a short interval.
Keep checking the official Railway Recruitment Board regional websites for fresh status updates.