...
One of the more common problems people have with their the first web service request is with authentication. The LMFS Leidos Flight Service web services use Basic HTTP authentication with Base64 encoding with preemptive authentication. As an example, given an email address and password me@letmein.com:MyPassw0rd!, you can run the following command in Linux to get the base64 encoding:
...
As part of creating your account, we will authorize the account to make web service calls. Once this is activated, you are authorized to make any of the web service calls available on the WSDL. If you chose to use credentialed filing, the web user will need to authorize you to make web service calls on their behalf. More on that in credentialed vs. non credentialed services here.