The issue you're facing likely stems from Akamai's security settings identifying your IBM i IP as potentially unsafe or unrecognized. Here are some steps you can take:

Check IP Reputation*  
   Visit a site like `talosintelligence.com` or `ipqualityscore.com` to check if your IP is blacklisted or has a poor reputation.

Contact Akamai or UPS Support  
   Since the API request is blocked at the server level, you may need to contact UPS/Akamai support with:
   - Your public IP
   - Request headers
   - Timestamp of the request
   - Any correlation or transaction ID from the error

Check for Missing Headers 
   Some APIs behind Akamai require specific headers (like `User-Agent`, `Accept`, or authorization tokens). Make sure these are present and correctly formatted.

Use Static IP (if possible)
   If your IP keeps changing, it may be flagged as suspicious. A static IP helps maintain trust.

Firewall & Rate Limiting
   Make sure your requests are not too frequent or malformed. Akamai will block requests if rate limits are exceeded.