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Salesforce FIELD_CUSTOM_VALIDATION_EXCEPTION specific path failure response

A Salesforce specific path failure note for FIELD_CUSTOM_VALIDATION_EXCEPTION: Salesforce failure caused by validation rule, governor limit, field-level security, API name drift, or automation order. It includes evidence, output examples, branches, and the smallest reliable fix.

lowFIELD_CUSTOM_VALIDATION_EXCEPTION8 min read
First command
grep -R "FIELD_CUSTOM_VALIDATION_EXCEPTION" ./logs
First evidence

Treat FIELD_CUSTOM_VALIDATION_EXCEPTION as a specific path failure case. First collect evidence for the route, rewrite rule, API path, host header, and upstream mapping.

Search queries
Salesforce FIELD_CUSTOM_VALIDATION_EXCEPTIONSalesforce error FIELD_CUSTOM_VALIDATION_EXCEPTIONSalesforce FIELD_CUSTOM_VALIDATION_EXCEPTION specific path failure response

When this happens

Use this when only one page, endpoint, static asset, or api route fails. Do not stop at the screen message; validate the route, rewrite rule, API path, host header, and upstream mapping first.

Symptom checklist

  • FIELD_CUSTOM_VALIDATION_EXCEPTION appears repeatedly in the Salesforce UI or logs.
  • profile, permission set, flow, trigger, owner state differs between successful and failed requests.
  • The issue appears only after separating data permission issue from Apex/Flow automation issue.
  • It often follows deploys, permission changes, configuration edits, or data refreshes.

Likely causes

  • FIELD_CUSTOM_VALIDATION_EXCEPTION specifically changes the investigation surface for Salesforce: verify the exact failing object, route, user, and timestamp before applying the broader pattern.
  • A validation rule blocks data that automation or import jobs now produce.
  • A trigger, Flow, or batch consumes governor limits before the final DML operation.
  • The integration user lacks field-level access to the referenced field.
  • A field API name differs between sandbox, package, and production.
  • Automation order changes the record before validation evaluates.
  • For the specific path failure case, the first useful clue is the route, rewrite rule, API path, host header, and upstream mapping.

First 1-minute checks

  1. Write down the first failure time, latest change, affected user, path, and object ID.
  2. Compare profile, permission set, flow, trigger, owner state for success and failure in the same window.
  3. Test the hypothesis: Salesforce failure caused by validation rule, governor limit, field-level security, API name drift, or automation order.
  4. Classify this as specific path failure: the route, rewrite rule, API path, host header, and upstream mapping.
  5. Capture current values before changing configuration.

First evidence

Treat FIELD_CUSTOM_VALIDATION_EXCEPTION as a specific path failure case. First collect evidence for the route, rewrite rule, API path, host header, and upstream mapping.

Output examples

Normal output

Working and failing paths use the intended host, status, and upstream.

Failing output

Only one route changes status, redirect target, content type, or upstream.

Output-to-action branches

  • Only one page, endpoint, static asset, or API route fails.
    Compare a working path and failing path, then fix routing, rewrite, upload limit, or upstream mapping.
  • The working and failing outputs differ.
    Act on the differing layer first: For FIELD_CUSTOM_VALIDATION_EXCEPTION, apply the fix only after reproducing the same condition and saving the before/after evidence for this exact code.
  • Command output is normal but users still fail.
    Separate browser cache, cookies, permissions, and network location before declaring it fixed.

Do not do this

  • Do not clear every cache before proving the route mapping.
  • Do not change multiple layers before identifying the failing layer.
  • Do not delete production data, grant broad permissions, or disable security controls as a first response.

Evidence quality

Auto-generated operator draft: includes issue-specific causes, commands, output branches, and unsafe-action warnings. Official-source links and real incident validation are queued for enrichment.

Commands to run first

grep -R "FIELD_CUSTOM_VALIDATION_EXCEPTION" ./logs
sfdx force:user:display
sfdx force:apex:log:list
sfdx force:data:soql:query -q "SELECT Id FROM User LIMIT 1"
grep -R "FIELD_CUSTOM_VALIDATION_EXCEPTION" force-app
sfdx force:apex:log:list
sfdx force:data:soql:query -q "SELECT Id, DeveloperName FROM ValidationRule LIMIT 10"
grep -R "FIELD_CUSTOM_VALIDATION_EXCEPTION\|LIMIT_EXCEEDED\|INVALID_FIELD" force-app ./logs
curl -I https://example.com/failing-path && curl -I https://example.com/working-path

Fix order

  1. Record the full FIELD_CUSTOM_VALIDATION_EXCEPTION message, failing URL, user, object ID, and latest change.
  2. Collect issue-specific evidence for Salesforce failure caused by validation rule, governor limit, field-level security, API name drift, or automation order.
  3. Compare the failing case with a successful case before editing settings.
  4. If this is the specific path failure branch, Compare a working path and failing path, then fix routing, rewrite, upload limit, or upstream mapping.
  5. Re-check with the same command and URL, then record the normal output.

Actions by cause

  • For FIELD_CUSTOM_VALIDATION_EXCEPTION, apply the fix only after reproducing the same condition and saving the before/after evidence for this exact code.
  • Identify the exact rule, field, flow, trigger, and integration user from debug logs.
  • Bulkify or split automation when governor limits are exhausted.
  • Grant field-level access only to the required profile or permission set.
  • Compare metadata names across orgs before changing payloads.
  • Add a test record that reproduces the failing validation path.
  • For the specific path failure branch, Compare a working path and failing path, then fix routing, rewrite, upload limit, or upstream mapping.

Verification metadata

  • operator-draft
  • official-reference-linked
  • 2026-07-23

Update queue

  • Review cadence
    weekly-source-review
  • Next enrichment
    Add one official-source check and one real output example for Salesforce FIELD_CUSTOM_VALIDATION_EXCEPTION.

Environment-specific checks

  • Shared hosting, proxies, VPNs, or CDN layers can change data permission issue from Apex/Flow automation issue results.
  • Do not trust only the Salesforce UI; compare command output.
  • Japanese hosting panels may show completion before DNS or SSL fully propagates.
  • Test from both office and external networks.

Prevent it next time

  • Store normal examples for profile, permission set, flow, trigger, owner state.
  • Add owner activation, permission sets, validation rules, trigger order to the release checklist.
  • Keep recurring errors in the same note format.
  • Split alerts by error rate, latency, certificates, disk, and permission changes.