USPS Realtime Error

We are trying to set up the USPS Shipping Method in CS-Cart 2.0.7. We have followed the instructions here [url]CS-Cart Documentation — CS-Cart 4.15.x documentation

We have our own USER ID given to us by USD in the Administration → Settings → USPS Tab.

Test Mode - Checked

Type of Mail - Package

Package Size - Regular

Machinable - True

Container (Priority Mail) - None

Container (Express) - None

Saved that screen.

Go to Shipping/Taxes Tab → Shipping Method-> USPS Priority → Edit

Then go down to the Test Link. Enter a weight 5.0 Lbs. Click Test →

Window pops up - We get this error…

API Authorization failure. RateV3 is not a valid API name for this protocol.

:confused: :confused: :confused:

Searched google, and we didn’t get many answers or people talking about this error with CS-Cart. Also searched the forums, no dice. We checked to make sure our PHP config has CURL and we are good to go there too… Any help is appreciated.



You probably have to contact the USPS to make sure your UserID is set up on the Production server. You cannot “test” USPS rates via CS-Cart - you have to automatically go right to the Production server. I set up an account on the Web Tools part of USPS and had to call them to have them switch my UserID over once I told them I was using CS-Cart as my ecommerce solution.

Also, if you’re using your regular USPS UserID, you need to make sure you have registered on the WebTools portion of USPS. The regular UserID for online labels, access to their site is not the same.

Hope this helps!




I’m getting the same error message.

I called USPS and they sent me an email with the production server URL’s. They said that I’m supposed to copy them inside the cart somewhere. Can anyone help?? I am beyond confused!

[COLOR=“Red”]Congratulations on completing your testing using the U.S. Postal Service’s Web Tools Application Program Interfaces (APIs). Your profile has been updated to allow you access to the Production Servers.

The URLs you will use for the Production Servers are:



I didn’t have to insert the URLs anywhere. I just made sure that my Web Tools ID was entered into the USPS shipping settings. The “test” checkbox should not be checked and make sure the following values in the fields:

Domestic USPS Section -

Package size: Regular

Machinable: True

Container (Priority Mail): None

Container (Express): None

Rest of the fields are blank.

These are my settings then I have a shipping method set up with Priority Mail as the type of USPS shipping.

Not sure what else could be wrong with your settings as long as your ID is on the Production server.

Hope something here helps. Good luck!



Thanks scase!

It works when i test the weight now.

However, when i add products to the cart, i am receiving the following message:


Unfortunately no shipping options are available for your location.

Please contact us and we will see about delivering to you.[/COLOR]

am i missing something else too?

Thanks for your help!

Do you have locations set up? You must set up locations. You have to set up a location for at least all of the places you want to ship to then set up additional locations if you want to use specific manual shipping methods for specific states, countries, etc.

Also, make sure you don’t have a membership assigned to the shipping method and you’re not using a user that is/isn’t assigned to that membership.

I know this might be a dumb question but your products have weights assigned to them, right? I was testing my shipping methods at one point and happened to choose a product that didn’t have a weight in it. Finally figured out my error.

I hope one of these things works to fix your problem.



Thanks Stephanie.

I finally figured out the problem. I had the Suppliers addon as active. After that was disabled, it worked! Jumping up and down

My membership status only has an all option assigned to all of the shipping methods. Is that an error?

No, the ALL membership is correct if you don’t have any other memberships set up. I do use memberships so can assign different shipping options to specific memberships if needed.

Glad to hear you figured out the problem. I’ve read that the Suppliers addon can be a bit of a headache sometimes.