The 400 BAD REQUEST error hits when the auto-routing rule tries to parse the body after the SIP trunk drops the Content-Type header. The script’s calling the Email ACD API to inject canned responses, but the HTML sanitizer breaks on nested <div> tags from the legacy fax gateway. Screenshot shows the JSON payload where the signature_stripping flag flips to false unexpectedly.
Console logs point to block 88 in the Architect flow. The transfer action routes to the generic queue because the regex fails on the new signature format. Parser just stops working.
The Email API documentation explicitly states that SIGNATURE_STRIPPING defaults to false when the CONTENT_TYPE header gets dropped or malformed during SIP trunk transit. You’re hitting that 400 because the routing engine completely chokes on the payload schema once the header vanishes. Here’s how to patch it up:
Force the flag at the API level instead of relying on the AUTO_ROUTING rule. You’ll need to send a direct PATCH to the communication settings before the HTML_SANITIZER kicks in.
Strip the nested divs manually in Architect. The legacy fax gateway is injecting malformed markup that breaks the default parser.
Check your KEY CONFIGURATIONS for the SIP trunk. The inbound routing profile is probably overriding the default email handling settings.
Drop a simple string replace expression into block 88 to catch the malformed tags early. Something like stringReplace(body, "<div[^>]*>", "") will clean up the fax gateway mess before it hits the sanitizer.
Run that right after the initial handshake completes. Honestly, the platform just needs a clean schema to work with. Looks like the fax gateway is just being stubborn. Keep an eye on the GENERAL routing limits too. The edge nodes start dropping packets once the payload crosses 25KB.
Is the tenant using the standard email connector or a custom SIP integration for this flow? Sorry for the newbie question, my English is not perfect. The error message is very vague sometimes, it’s just a generic 400 with no clear details about the HTML structure.
Instead of forcing the flag with a PATCH request like the suggestion above, maybe the fix is inside the Architect flow settings. In Genesys Cloud, the signature stripping logic works differently than NICE CXone or Five9. Those competitors allow regex patterns to strip the signature directly in the routing script, but Genesys Cloud requires the API to handle the body parsing before the sanitizer sees the nested div tags.
Try adding a Set Data block before the Email ACD action. You can manipulate the body content string to remove the problematic tags manually. This avoids the header drop issue completely.
Talkdesk handles this with a simpler toggle in the admin console, so the Genesys Cloud approach feels more complex for devops tasks. The boundary alignment in the API also breaks if the payload gets too large during the sync.
This usually fixes the schema error without touching the trunk headers. The 400 error should stop if the body is clean before the API call.
The validation schema mismatch is exactly what’s causing the 400 BAD REQUEST. When the SIP trunk strips the Content-Type header, the inbound parser doesn’t just assume plain text. It actually rejects the payload structure entirely because the signature stripping module requires a specific HTML hierarchy to locate the signature boundary. That’s why the signature_stripping flag flips to false in the logs. The platform can’t evaluate the flag if the content type is ambiguous. Real pain when the trunk drops that header.
Step one is tracing the raw interaction data to confirm the header drop. You need to verify that the content_type field is null for these failed interactions. Run this OData query against the reporting endpoint to pull the details.
GET /api/v2/reporting/interactions/odatalive?filter=interaction_type eq 'EMAIL' and status eq 'FAILED'&select=interaction_id,body,content_type,signature_stripping
You’ll see the content_type coming back empty. Once that’s confirmed, the fix isn’t in the Architect flow settings. It’s in the Email API configuration for that specific connector. You have to force the default content type handling so the parser doesn’t bail out during validation. Send a PATCH to the email settings endpoint with the default_content_type set to text/html. This forces the signature stripper to run even when the header is missing.
The default_content_type property is the critical piece here. Without it, the signature_stripping flag gets ignored during the validation phase. You don’t need to touch the routing rules. Just update the connector config. The 400s will drop off.
Cause: It’s rejecting the payload because the missing Content-Type header breaks the HTML sanitizer schema.
Solution: You’ll bypass the Architect routing rule and patch the communication settings directly. What’s the exact 400 error code returned on that endpoint?