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Order Issues

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Failed Orders

Important: A returned order ID with HTTP 200 does not guarantee the order was successfully processed. Failed orders don’t generate user-visible errors unless a required field is missing.
To ensure your order was successfully processed, always verify its status via the order stream. Do not rely solely on HTTP 200 responses or returned order IDs.
Common failure reasons:
  • Invalid Account
  • Expired Instrument
  • Insufficient Balance

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Connection Issues

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Error 464

When receiving a 464 error in prod or pre-prod environments, verify that the Host header is set correctly: 
Host: rest.preprod.polymarketexchange.com
OR 
Host: rest.prod.polymarketexchange.com
Without this header, requests are routed to gRPC by default instead of REST.

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Timeout / No Response

If curl commands hang without returning a response: Step 1: Verify DNS Configuration Use the complete service name endpoint to test connectivity: 
https://traderapi.us-east-1.privatelink.preprod.polymarketexchange.com/auth/v1beta1/register
If this URL works but your DNS/CNAME doesn’t, the issue is with your DNS configuration. Step 2: Check Security Group Settings If the full endpoint also times out, review your VPC security group settings:
  • Set inbound rules to 0.0.0.0/0 for all traffic
  • Set outbound rules to 0.0.0.0/0 for all traffic These settings are suggested for testing only and not recommended for production Security Groups

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Curl Command Drops to Blinking Cursor

If your curl command drops to a new line with a blinking cursor (>_), this indicates a formatting issue with the command itself—not a connection problem. Common causes:
  • Missing quotation marks
  • Missing escape characters
  • Malformed command syntax

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Platform-Specific Issues

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Windows & Python HTTP/2

Windows instances and Python applications may encounter HTTP/2 compatibility issues:
  • Windows: Ensure HTTP/2 is enabled
  • Python: Use the httpx library instead of requests

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AWS Connectivity

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Can’t Connect to Service

If your AWS instance cannot find the service, verify your subnets match our availability zones.
Availability zone letter indicators (e.g., us-east-1a) can be mapped differently across AWS accounts. At least one availability zone ID must match.
Production Availability Zones:
  • use1-az1
  • use1-az2
  • use1-az6
Pre-Production Availability Zones:
  • use1-az1
  • use1-az2
  • use1-az4
Subnet matching only applies when connecting from within AWS us-east-1. Connections from other regions are mapped automatically.