Plaid + Chase Connectivity Issue via API

Plaid + Chase Connectivity Issue via API

Plaid + Chase OAuth Integration — "Invalid Credentials" After Successful OAuth Flow

The Problem:
We have a production Plaid integration (Node.js/Express) that connects bank accounts via Plaid Link. American Express and Capital One connect and sync perfectly. Chase fails every time with "Username or password incorrect" AFTER the OAuth flow completes successfully.

The Flow:
1. User clicks Connect Bank → Plaid Link opens
2. User selects Chase → Plaid fires OPEN_OAUTH event
3. User redirects to Chase's website and logs in successfully
4. Chase redirects back to our app with oauth_state_id
5. Plaid Link re-opens with receivedRedirectUri
6. Plaid shows "Username or password incorrect" — connection fails

What We've Verified:
- Plaid environment: Production
- Chase institution (ins_56) status: HEALTHY, OAuth: true
- Chase OAuth enabled in Plaid Dashboard (Team Settings)
- Redirect URI registered correctly in Plaid Dashboard
- Link token creates successfully (transactions product only)
- No issues on Chase's "Linked apps & websites" settings
- Works fine for Amex and Capital One
- Same error in incognito/different browsers

Our Stack:
- Node.js + Express backend
- Plaid Node SDK, API version 2020-09-14
- Products: ['transactions']
- Hosted on Railway, domain: custom domain with HTTPS

What We Need:
Someone who has successfully connected Chase in production via Plaid OAuth to diagnose whether this is:
1. A Plaid account configuration/approval issue (Chase Data Access Agreement?)
2. A code/API configuration issue we're missing
3. Something else entirely

Ideal Candidate:
- Has shipped a production Plaid integration with Chase working
- Familiar with Plaid OAuth flow, Chase-specific requirements
- Can diagnose quickly — we have full error logging and server access

Budget: Hourly, happy to pay well for a fast resolution.