USPS plugin failing after 4.3 upgrade.

Hi, I just had to roll back my attempt to upgrade from 4.20 -> 4.30. Was going well until I realized I wasn't getting nay shipping calculations done. Oops. I realizd I never installed the USPS plugin after the 4.30 upgrade. I downloaded the latest plugin from https://www.nopcommerce.com/en/shipping-plugin-for-usps, and now the Calculate shipping step throws an error message of "Error Desc: XML Syntax Error: Please check the XML request to see if it can be parsed.(B). USPS Help Context: ."

Any idea about this? I've rolled back my production website to 4.20 and it is working fine again. But I also have replicated this issue in my dev environment if you would need any additional info.

I've never seen that error before.  Unfortunately the USPS plugin does not have a tracing option (to send request XML to system log).  I can only suspect that there's a bad character in your request.  Check your user name, password, address fields, to make sure your not using unusual characters (e.g. diacritics,  etc.)

Nothing special about the address. This happens with the default John Smith, 21 West 52nd Street, New York, New York 10021, United States address that appears in Nopcommerce after install along with all the other saved addresses I'm throwing at it that worked just fine in 4.20

What about your userid & password?  any of these characters:  & < > " '  
(those last two are double and single quote)

I currently did the upgrade to 4.3 from 4.2.
My USPS plugin is working fine SupportedVersions 4.3 & Version 1.48.
I did have to update the url to use api@ https://secure.shippingapis.com/shippingapi.dll in the in the
Shipping Providers USPS settings.

New York wrote:

None of those specifically, although there were other special characters in the password. I requested new credentials for the USPS API. Password didn't have any special characters and the plugin seems to be working fine with them.