While candidate rejection is usually determined by AI scoring algorithms, applications can also fail due to technical interference, frontend-backend friction, or malicious disruptions during transmission.
- Race Conditions on Backend Handlers: A race condition occurs when an ATS server processes concurrent asynchronous operations out of order. If a candidate’s final form submission packet arrives at the exact same millisecond as the asynchronous resume file-upload handler, a backend timing conflict can occur. If the database processes the form completion before the file object registers, the server drops the attachment, resulting in a sudden crash or a “Bad Request” error while appearing normal on the user’s screen.
- Asymmetric Rate Limiting and Session Drops: Automated Web Application Firewalls (WAFs) or strict backend rate-limiting rules can misinterpret multi-step form navigation or fast input typing as bot activity. If a session token drops or expires mid-form due to aggressive token rotation policies, the server silently revokes authorization, causing subsequent payloads to fail authentication and rejecting the entire application submission.
- Malicious Local Script Injection and Fingerprinting: Compromised networks or malicious scripts running on vulnerable job boards can manipulate DOM elements locally. This can alter form input fields, inject invisible validation traps that flag human applicants as bots, or intercept session cookies to block successful data transmission.
- API Payload Mismatches: If an ATS updates its backend schema without synchronizing frontend form validation, legitimate applicant payloads can fail strict JSON schema validation checks on the server. This causes silent validation drops where the user sees a perpetual loading spinner or a generic error code, permanently locking them out of the recruitment pipeline.
Example of Ontario Pension Board (OBP) – Site Goes Down
Example of Healthcare of Ontario Pension Plan (HOOPP )- Various Error Codes
Example of Honeywell – Diversity Questionnaire Dropdown Menu Restricted to “White”
Example of ADP – Proxy Error
Example of Holt Renfrew – Contact Administrator
Example of Chanel – Access Denied
