Using 1.3.8a version of ZenCart and the latest USPS 2010_0104_b module.
I had not used USPS in a year or so and did all sorts of testing and could not get it to return a rate. I finally found a valid rate test, so I knew my account was still active. The test I performed follows, for those who want to test using HTTP. Note, change the xxxxx to your account ID.
http://production.shippingapis.com/shippingAPI.dll?API=RateV3&XML=<RateV3Request USERID="xxxxx"><Package ID="0"><Service>All</Service><ZipOrigination>96704</ZipOrigination><ZipDestination>30066</ZipDestination><Pounds>1</Pounds><Ounces>1</Ounces><Size>REGULAR</Size><Machinable>FALSE</Machinable></Package></RateV3Request>
This should give you a bunch of rates from Hawaii to Georgia (where I am now and where I used to live) [By the way, Hawaii has more tsunamis than Georgia, but Georgia has more tornados]
Anyway, The above test worked but I was still not able to get any respose back in email with debug turned on. All I would get is the text:
"(You can turn off this debug email by editing your USPS module settings in the admin area of your store.) "
I knew the module should be working and then it struck me. I have had the same issue with other attempts to run applications of this server.
My hosting company implimented a new security process which is called "OUTGOING CONNECTIONS MANAGER". It notices that your server is trying to communicate with another server and takes action. In my case, it automatically adds the first 10 IP addresses to the allow list, then starts blocking addresses. That is what kept me from accessing USPS which uses many different IP's.
This software blocking appears to be used to ensure that someone has not turned your account into a zombie which is randomly trying to attack multiple IP addresses around the world. This is useful and a nice feature, as long as you remember to configure it or disable it.
So my suggestion is if you have followed the instructions to add the new module, and have configured things correctly in Zen-cart, then if the URL above works and your cart does not return any debug info (assuming you turned it on), you might check with your hosting compny to see if they also use a connection manager to block IP addresses.
Note also, that this connection manager would also effect FedEx and Authorize.Net and so on. In my case, the first 10 server accesses were automatically allowed and the rest denied. Dpending upon which access attempts came first, other services may have randomly been blocked, so if customers first tried using USPS and the FedEx and then USPS again, not all of the various USPS addresses would have been allowed and some accesses would be denied if they started using IPs that were not allowed in the 1st 10.
This may explain why some people have what look to be random outages of shipping and payment services.
I hope this info helps someone.
