Which url should use for testing incorporation?

i got error by using the test url - http://xmlalpha.companieshouse.gov.uk/v1-0/xmlgw/Gateway for testing incorporation . the error liks - Error: Failed to connect to xmlalpha.companieshouse.gov.uk , connection refused. Can anyone help please?

The correct URL for all filings (both test and live) is:
https://xmlgw.companieshouse.gov.uk/v1-0/xmlgw/Gateway

SDN

but when i using the above mentioned url with the “GatewayTest” tag in my xml, i got error like 502 fatal invalid testmode selected.please help.

A 502 error indicates that the correct sender ID details have not been used, or that the sender ID details have not been correctly MD5# treated.

SDN