so the response from payapl shows the following error:
<LongMessage xsi:type="xs:string">Security header is not valid</LongMessage>
This error occurs when there is a problem with the API credentials being used. It is usually caused if the API Credentials are for the Sandbox, and you are using the live server, or vie versa, or if you have not excepted the billing agreement.
Sometimes, the credentials payapal generates are just bad, you may have to request new ones.
also you are getting the following error from fed ex:
<Message>Ground Service Type must be Ground Home Delivery or FedEx Ground</Message>
You have set the service type to FedEx 2 day:
try using Ground Home Delivery or FedEx Ground instead.