I'm trying to get this working on Zencart 1.5.5f and keep getting an error on the checkout page that says:

"An error occurred in obtaining USPS shipping quotes.
If you prefer to use USPS as your shipping method, please try refreshing this page, or contact the store owner."

I've turned on debugging and the log has the following (I've replaced the username):

2020-11-12 18:28:26: USPS build: 2020-09-24 K11

Server: production
Quote Request Rate Type: Retail
Quote from main_page: checkout_shipping
USPS Options (weight, time): --none--
USPS Domestic Transit Time Calculation Mode: CUSTOM
Cart Weight: 0.5
Total Quote Weight: 0.5 Pounds: 0 Ounces: 8
Maximum: 50 Tare Rates: Small/Medium: 0 Large: 0
Handling method: Box Handling fee Domestic: $0.00 Handling fee International: $0.00
Decimals: 3
Domestic Length: 8.625 Width: 5.375 Height: 1.625
International Length: 9.50 Width: 1.0 Height: 5.50
All Packages are Machinable: False
Enable USPS First-Class filter for US shipping: True
Sorts the returned quotes: Unsorted

ZipOrigination: 92065
ZipDestination: Postcode: 32570 Country: United States City: Milton State: Florida
Order SubTotal: $34.95
Order Total: $34.95
Uninsurable Portion: $0.00
Insurable Value: $34.95

2020-11-12 18:28:26: Sending request to USPS

2020-11-12 18:28:41: ==================================

SENT TO USPS:

<RateV4Request USERID="**********"><Revision>2</Revision>
<Package ID="0"><Service>First Class</Service><FirstClassMailType>FLAT</FirstClassMailType><ZipOrigination>92065</ZipOrigination><ZipDestination>32570</ZipDestination><Pounds>0</Pounds><Ounces>8</Ounces><Container>VARIABLE</Container><Size>REGULAR</Size><Value>34.95</Value><Machinable>FALSE</Machinable></Package>
<Package ID="1"><Service>First Class</Service><FirstClassMailType>PARCEL</FirstClassMailType><ZipOrigination>92065</ZipOrigination><ZipDestination>32570</ZipDestination><Pounds>0</Pounds><Ounces>8</Ounces><Container>VARIABLE</Container><Size>REGULAR</Size><Value>34.95</Value><Machinable>FALSE</Machinable></Package>
<Package ID="2"><Service>MEDIA</Service><ZipOrigination>92065</ZipOrigination><ZipDestination>32570</ZipDestination><Pounds>0</Pounds><Ounces>8</Ounces><Container>VARIABLE</Container><Size>REGULAR</Size><Value>34.95</Value><Machinable>FALSE</Machinable></Package>
<Package ID="3"><Service>PARCEL</Service><ZipOrigination>92065</ZipOrigination><ZipDestination>32570</ZipDestination><Pounds>0</Pounds><Ounces>8</Ounces><Container>VARIABLE</Container><Size>REGULAR</Size><Value>34.95</Value><Machinable>FALSE</Machinable></Package>
<Package ID="4"><Service>PRIORITY COMMERCIAL</Service><ZipOrigination>92065</ZipOrigination><ZipDestination>32570</ZipDestination><Pounds>0</Pounds><Ounces>8</Ounces><Container>VARIABLE</Container><Size>REGULAR</Size><Value>34.95</Value><Machinable>FALSE</Machinable></Package>
</RateV4Request>


RESPONSE FROM USPS:

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CommErr (should be 0): 28 - connect() timed out!

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USPS Country - $order->delivery[country][iso_code_2]: United States $this->usps_countries: US
Domestic Services Selected: