USPS stopped working with my sites using 1.3.9b

Two of my Zencart sites I have tried to use USPS as well as UPS for shipping. One uses 1.3.8a and the other uses 1.3.9b I haven't installed any patches or fixes on either but the only one that has USPS showing up in the "Estimate Shipping" window is the site using 1.3.8a. This is baffling me since the from what I've been reading the newer version should be the one with no problems and the 1.3.8 site would need the shipping module updated.

the sites are

b u d d s w h o l e s a l e . com (1.3.8a USPS seems to be working)
j j d i g i t a l w o r l d . com (1.3.9b USPS is not working)

Any idea of how i can begin to troubleshoot this?

Did you set up the USPS module for 139b??

admin panel/ modules/ shipping/ USPS

Yes, it is installed and enabled and the username is entered and i made the call to the USPS and received the email after asking to be moved to the production server.... all in all everything i think that needs to be done is done....

Thanks for the update..

Is the 1.3.9b site a new install or an upgraded site?

The 1.3.9b site is a new install, not upgraded.

Try uninstalling and reinstalling the module from your Admin.

Ok, i un-installed and re-installed USPS module in the Admin... put in the user name.... production server. No luck, still only UPS is showing when i go to buy something and click Estimate shipping.

Is there a way to test if there's errors with the installation or something? This same thing is happening with a number of other sites that I've recently installed with the same version. But the sites with previous versions don't seem to have problems.

Resolved: It was a simple typo in the Shipping Zip code. It did not affect UPS shipping quotes from working but USPS just wouldn't show up in the Estimator due to a ZIP Code that it did not recognize under ADMIN-Configuration-Shipping/Packaging-Postal Code.

Side note, I was never able to get the account switched to the production server at USPS by sending them an email (there were no typos in that!), they just never responded, I HAD to call the 1-800 number and it was done immediately.